摘要
M型锶铁氧体（SrFe_(12)O_(19)）是一种具有良好磁性能的重要永磁材料，因为其制备原材料丰富，制造成本低廉，物理和化学性能稳定和抗氧化等优点，在最近几年得到了广泛的研究，并且被大量应用于无线通讯，磁记录材料，磁光材料和微波器件中。但是，与Nd_2Fe_(17)B材料相比，SrFe_(12)O_(19)材料的磁性能相对较低（饱和磁化强度为51emu/g，矫顽力为4733Oe），这严重制约了它的应用。因此，改善SrFe_(12)O_(19)材料的磁性能就成为这种材料能否被广泛应用的重要前提。
M型SrFe_(12)O_(19)属于六角晶系，具有典型的磁铅石结构，作为一种永磁材料，其磁性来源于具有磁性行为的Fe~(3+)离子和具有单一易磁化轴的磁晶各向异性。长期以来，研究工作主要是利用各种方法和技术进行元素掺杂，通过提高SrFe_(12)O_(19)的內禀磁矩和磁晶各向异性，实现其饱和磁化强度和矫顽力的增加。例如：通过溶胶-凝胶法合成的Zn-Sn共掺的SrFe_(12)O_(19)，其饱和磁化强度可以达到81emu/g；通过自蔓延法合成的Nd-Cd共掺的SrFe_(12)O_(19)，饱和磁化强度为76emu/g；通过化学共沉淀技术合成的Zr-Cd共掺的SrFe_(12)O_(19)，其饱和磁化强度可以达到80emu/g，而矫顽力却只有1256Oe；以及溶胶-凝胶法合成的Nd-Co共掺的锶铁氧体，其矫顽力可以达到7120Oe；利用化学共沉淀技术合成Zn-Zr共掺的锶铁氧体，其矫顽力为1720Oe；La掺杂的锶铁氧体的饱和磁化强度和矫顽力也能达到66emu/g和7000Oe等等。这些阳离子替代虽然实现了饱和磁化强度的增强，但矫顽力改善幅度很小，远不及Nd_2Fe_(17)B材料的矫顽力。因此，选择合适的制备方法和掺杂元素提高M型SrFe_(12)O_(19)材料的矫顽力已成为备受关注的热点问题。除了元素掺杂方法外，改变SrFe_(12)O_(19)形成的热力学过程，如：利用某种方法和技术调整其形成过程中的中间相，或提高SrFe_(12)O_(19)的内应力等，也可能成为提高SrFe_(12)O_(19)矫顽力的有效途径。但关于这方面的研究目前尚未见相关报道。
本论文围绕着锶铁氧体材料矫顽力普遍较低这一关键科学问题，通过采取合适的制备方法和技术，调控SrFe_(12)O_(19)形成的热力学过程，选取合适的掺杂元素和掺杂方法对SrFe_(12)O_(19)掺杂，开展了提高SrFe_(12)O_(19)矫顽力的研究工作，并取得了如下的结果：
利用常规烧结和机械合金化结合高温热处理开展了M型SrFe_(12)O_(19)材料的制备、表征和磁性能的研究工作，研究结果表明：在机械合金化结合高温热处理法中，首先α-Fe_2O_3和SrCO_3按摩尔比为3：1的混合物球磨120h形成尖晶石结构的Fe_3O_4，而Sr处于Fe_3O_4的晶界处，结合球磨120h样品的TG曲线的变化情况，发现球磨120h样品在500-800℃温度区间形成SrFe_(12)O_(19)。以同样比例的α-Fe_2O_3和SrCO_3为原料，利用常规烧结制备SrFe_(12)O_(19)的过程中，首先是α-Fe_2O_3和SrCO_3反应生成具有立方结构的SrFeO2.97中间相，然后SrFeO2.97与α-Fe_2O_3在1000℃反应形成SrFe_(12)O_(19)，其形成温度比机械合金化法高出很多。并且，以机械合金法制备的SrFe_(12)O_(19)的饱和磁化强度和矫顽力分别是60.65emu/g和5481.1Oe，其矫顽力比常规烧结方法制备的SrFe_(12)O_(19)的矫顽力大（3932.4Oe）。在两种制备方法中，由于所经历的中间相不同，使SrFe_(12)O_(19)的形成温度、磁性能和样品的相组成不同。球磨有利于SrFe_(12)O_(19)形成温度的减低、矫顽力的提高和单一相样品的获得。
以Sr(OOCCH_3)_2·0.5H_2O，C_(15)H_(21)FeO_6和Polyvinylphrrolidone，M.W.13000000为初始原料，通过溶胶-凝胶法配制出胶体溶液，并利用旋涂法在蓝宝石衬底上生长出择优的SrFe_(12)O_(19)薄膜材料，室温VSM测试结果表明，按着Sr：Fe=1：12和Sr：Fe=1：10不同条件配比，在900℃退火条件下制备出的SrFe_(12)O_(19)薄膜材料，其矫顽力分别达到6486.3Oe和6279.9Oe，远大于SrFe_(12)O_(19)块体材料的矫顽力，对锶铁氧体薄膜的研究具有重要的意义。
利用甘氨酸-硝酸盐法制备出不同Al掺杂量的M型SrFe_(12)O_(19)的前驱体粉末，然后通过热处理的方法在700℃到1250℃条件下制备出Al掺杂M型SrFe_(12)O_(19)(SrAl_xFe_(12-x)O_(19)(0≤x≤4))。研究发现：随着热处理温度的升高和Al名义掺杂量的增大，在SrAl_xFe_(12-x)O_(19)化合物中Al的含量也在不断增大。因为非磁性的Al~(3+)离子只替代在2a和12k晶格位上自旋向上的Fe~(3+)离子，并且Al~(3+)离子的离子半径小于Fe~(3+)离子，必然会导致SrFe_(12)O_(19)晶格常数的变小，进而使2a和12k晶格位处的磁晶各向异性增强。因此，随着SrAl_xFe_(12-x)O_(19)中Al含量的增加，其饱和磁化强度不断降低而矫顽力逐渐增大。但是，当4个Fe~(3+)离子全部被Al~(3+)离子替代时，晶胞的净磁矩就会减小到零，这使得磁性Fe~(3+)离子之间的相互作用减弱，从而导致SrAl_xFe_(12-x)O_(19)矫顽力降低，样品也由原来的亚铁磁性向反铁磁性转变。当Al的名义掺杂量为x=4时，在1000℃条件下热处理后的样品的矫顽力达到了17570Oe，其远远高于SrFe_(12)O_(19)矫顽力的大小（5356Oe），并且已经超过了Nb_2Fe_(17)B矫顽力的大小(15072Oe)。
对经1100℃烧结形成的SrAl_xFe_(12-x)O_(19)化合物在5-300K的温度范围内进行了磁化强度随温度变化（M-T）的测量，结果表明:未掺杂SrFe_(12)O_(19)的M-T曲线表现出明显的P型亚铁磁性特征，即，磁化强度随温度的升高先增大，到达44K时，其磁化强度达到最大值，这个温度称为转变温度，当温度高于转变温度后，磁化强度随温度升高而降低；当Al掺杂到SrFe_(12)O_(19)中时，转变温度随Al掺杂量增加而降低，当名义Al掺杂量高于3时，在测量温度范围没有观察到转变温度，即，P型亚铁磁特征消失。根据Neel理论，未掺杂SrFe_(12)O_(19)的P型亚铁磁性可归因于其Fe~(3+)离子分布在五种不同晶格位上，并且，自旋向上的Fe~(3+)离子数目多于自旋向下的。由于自旋向上的Fe~(3+)离子晶格的磁化强度随温度的变化与自旋向下的不同，导致SrFe_(12)O_(19)表现出P型亚铁磁特征的M-T曲线。当Al掺杂到SrFe_(12)O_(19)中时，非磁性的Al~(3+)离子替代自旋向上的Fe~(3+)离子，导致自旋向上和自旋向下的Fe~(3+)离子数趋于相同，进而使得Al掺杂的样品随着Al掺杂量的增大，磁化强度逐渐减小，转变温度逐渐降低。当Al的掺杂量达到x=3时，转变温度完全消失。当Al掺杂量为x=4时，其自旋向上和自旋向下的Fe~(3+)离子数相等，样品逐渐由亚铁磁性向反铁磁性转变。
利用甘氨酸-硝酸盐法进行了稀土元素La和Dy以及过渡族元素Co掺杂的M型SrFe_(12)O_(19)材料的制备和表征。研究结果表明：对于稀土元素La掺杂的M型SrFe_(12)O_(19)材料来说，由于La~(3+)的离子半径小于Sr~(2+)离子，使得替代后SrFe_(12)O_(19)晶体结构中2b晶格位置处的对称性发生了变化，所以导致Sr_(1-x)La_xFe_(12)O_(19)样品的矫顽力随着La掺杂量的增加而增大，但三价La3+的离子替代二价Sr2+离子，使得部分Fe~(3+)离子转变为Fe2+离子，导致了饱和磁化强度的减小。对于Dy掺杂M型SrFe_(12)O_(19)来说，Dy同样是替代Sr位，但是其效果要比La差很多，其矫顽力和饱和磁化强度都比未掺杂的SrFe_(12)O_(19)小。而过渡族元素Co掺杂的M型SrFe_(12)O_(19)材料，当Co掺杂量达到x=0.5时，在1100℃热处理后我们得到了单一的SrCo_(0.5)Fe_(11.5)O_(19)相，其饱和磁化强度为71.23emu/g，很接近SrFe_(12)O_(19)的理论值，但矫顽力却只有2520.7Oe。由此可见，Co掺杂对SrFe_(12)O_(19)的饱和磁化强度的提高有很大帮助。
M-type strontium hexaferrite (SrFe_(12)O_(19)) is an important permanent magneticmaterial with better magnetic properties. Since it has abundant raw material, lowmanufacturing cost, stable properties and anti-oxidation, it has attracted extensiveinterests in past decades, and been widely used in telecommunication, magneticrecording medium, magneto-optics and microwave devices. However, in comparisonwith Nd_2Fe_(17)B, the magnetic properties of SrFe_(12)O_(19)(saturation magnetization of51emu/g and coercivity of4733Oe) are much lower, which seriously affects itsapplication. Therefore, improvement of the magnetic properties is very important forthe strontium hexaferrtie.
M-type SrFe_(12)O_(19)is a permanent magnetic material with hexagonal ferrites anda magnetoplumbite structure, its magnetic properties originate from the Fe3+ions,which present a magnetic moment and magneto-crystalline anisotropy with singleeasy magnetization axis. Over years, many studies in this field have focused onvarious methods and techniques of element doping, by improving the intrinsicmagnetic moment and magnetic anisotropy of SrFe_(12)O_(19)to realize the improving ofmagnetization and coercivity. Such as: Zn-Sn co-substituted strontium hexaferrite issynthesized by sol-gel method, with the saturation magnetization value of81emu/g;Nd-Cd co-substituted strontium ferrite is prepared by self-propagating combustionmethod, with the saturation magnetization value of76emu/g; Zr-Cd co-substituted strontium ferrite is prepared by chemical co-precipitation method and its saturationmagnetization value reaches80emu/g; but the coercivity value only achieves1256Oe. And Nd-Co co-substituted strontium hexaferrite with the coercivity value of7120Oe is synthesized by sol-gel method; Zn-Zr co-substituted strontium ferrite isprepared by chemical co-precipitation method, and the coercivity value is1720Oe;The saturation magnetization and coercivity of La substituted strontium hexaferritereaches66emu/g and7000Oe, respectively etc. Althogh these cationic substitutionenhanced saturation magnetization, the coercivity of the M-type hexaferrites is notincreased obviously, and is still much smaller than that of Nd_2Fe_(17)B. Therefore,choosing the appropriate preparation methods and doping element to improve thecoercivity of M-type SrFe_(12)O_(19)have become a hot issue of concern. In addition tothe element doping methods, changing the thermodynamic process of SrFe_(12)O_(19)formation may also become an effective way to improve the coercivity of SrFe_(12)O_(19).Such as: use of certain methods and techniques to adjust the intermediate phase inthe formation process, or improve the internal stress of SrFe_(12)O_(19). However, researchin this area has not been reported yet.
This paper mainly concerns the key scientific question of the generally lowcocervity of strontium hexaferrite, by taking the appropriate preparation methods andtechnical to realize the regulation of the thermodynamic processes of SrFe_(12)O_(19), andselect suitable doping elements and doping methods to realize SrFe_(12)O_(19)doping. Aseries of research works have carried out to improve the coercivity of SrFe_(12)O_(19), andhave achieved the following results:
The research work for preparation, characteristic and magnetism performanceof M-type SrFe_(12)O_(19)were developed in conventional sintering and mechanical alloymethod. The research results show: in the mechanical alloying process, firstly, theFe_3O_4with spinel structure is fabricated by mechanochemical reaction of α-Fe_2O_3and SrCO_3with molar ratio of3:1in high energy ball milling, the120h-milledmixture consists of Fe_3O_4and Sr existing in the grain boundary. According to thechange of TG curve of120h-milled mixture, it is found that the SrFe_(12)O_(19)is synthesized between500℃and800℃. In the conventional sintering process, theα-Fe_2O_3reacts with SrCO_3to form an intermediate phase of SrFeO2.97first, and thenthe SrFeO2.97reacts with α-Fe_2O_3to form SrFe_(12)O_(19)at the sintering temperature of1000℃, implying that the reaction temperature is much higher than that of the120h-milled mixture. The saturation magnetization and coercivity of SrFe_(12)O_(19)which is prepared by mechanical alloying method is60.65emu/g and5481.1Oe,respectively, its coercivity is much larger than that of SrFe_(12)O_(19)which is prepared byconventional sintering method (3932.4Oe). In the two preparation methods, theexperiencing of different intermediate phase leads to the difference of formationtemperature, magnetic properties and sample phase composition of SrFe_(12)O_(19).Mechanical alloying method is conducive to the formation temperature reduction,the improvement of the coercivity and the obtaining of single-phase samples ofSrFe_(12)O_(19).
Sr(OOCCH_3)_2·0.5H_2O, C_(15)H_(21)FeO_6and Polyvinylphrrolidone, withM.W.13000000are the initial raw material, use sol-gel method to prepare thesolution. By using the spin-coated method, the preferred orientation thin films ofSrFe_(12)O_(19)are fabricated on sapphire (006) substrate. The VSM measurementindicates that the coercivity of SrFe_(12)O_(19)films which prepared in the differentmatching of Sr:Fe=1:12and Sr:Fe=1:10and annealed in air at900℃, is6486.3Oeand6279.9Oe, respectively, much larger than that of SrFe_(12)O_(19)bulk materials, whichis significant for the study of strontium ferrite thin films.
A series of strontium hexaferrite compounds SrAl_xFe_(12-x)O_(19)(0≤x≤4) have beensynthesized by glycin-nitrate method and subsequent heat treatment has been takenin the temperature ranging from700℃to1250℃. It is found that the Al in thestarting mixture almost all incorporated into SrFe_(12)O_(19)by substituting for Fe to formSrAl_xFe_(12-x)O_(19)compounds. The content of Al in the SrAl_xFe_(12-x)O_(19)increases withincreasing heating temperature and the nominal Al content. Since the nonmagneticAl~(3+)ion only occupies the Fe~(3+)ions site at2a and12k with spinning upward in theSrAl_xFe_(12-x)O_(19)and has smaller ionic radius comparing with Fe~(3+)ion, the latticeconstant decreases and the magneto-crystal anisotropy of2a and12k sites increaseswith increasing the Al content doped in the SrAl_xFe_(12-x)O_(19), hence, resulting in reduction in the saturation magnetization of the SrAl_xFe_(12-x)O_(19)and enhancement inthe coercivity with increasing heating temperature and the nominal Al content.However, when the4Fe~(3+)ions are almost replaced by Al~(3+)ions, the net magneticmoment will be closed to zero, that will weaken the exchange interaction betweenFe~(3+)ions, resulting in the decrease of coercivity. The largest coercivity obtained inthe SrAl4Fe8O19sintered at1000℃is17570Oe, which is much larger than the valueof the SrFe_(12)O_(19)(5356Oe) and exceeds the coercivity of Nb_2Fe_(17)B (15072Oe).
For the SrAl_xFe_(12-x)O_(19)compound that formed at sintering temperature of1100℃, a series of measurements about the magnetization changes with temperature(M-T curve) have been carried out, the results show that: The M-T curve of undopedSrFe_(12)O_(19)shows obvious P-type ferrimagnetic characteristics, magnetization firstincreases with the increasing temperature to reach44K, meanwhile themagnetization reaches its maximum, this temperature is called the transitiontemperature, when the temperature is higher than the transition temperature, themagnetization decreases with the increasing temperature; Once Al was doped intoSrFe_(12)O_(19),the transation temperature decreased with the increasing of Al dopingcontent; when the nominal Al doping content is higher than x=3, no transitontemperature was observed in the measurement, which means P-type ferrimagneticcharacteristics disappeared. According to Neel theory, the P-type ferrimagneticcharacterstics of undoped SrFe_(12)O_(19)can be attributed to its Fe~(3+)that distributed infive different lattice sites, and the number of Fe~(3+)with spinning upwards is muchmore than spinning downwards. Due to the difference in magnetization variationwith temperature between Fe~(3+)sublattices with spinning upwards and downwards,the SrFe_(12)O_(19)shows M-T curves of P-type ferrimagnetic characteristics. Once Alwas doped in the SrFe_(12)O_(19), non-magnetic Al~(3+)ions substitute for spinning upwardsFe3ions, resulting in the trend of quantity balance between Fe~(3+)spinning upwardsand downwards, thus for the Al doped samples, with the increase of Al dopingcontent, transiton temperature reduces and the magnetization decreases gradually.When Al reaches the doping content of x=3, the transition temperature disappearedcompletely. When the doping content of Al reaches x=4, the number of Fe~(3+)spinningupwards and downwards is equal, the sample realized transition from ferrimagneticto antiferromagnetic gradually.
Preparation and characterization of rare earth element La, Dy and transitionelement Co substituted M-type strontium hexaferrite which prepared by glycin-nitrate method have been carried out. The results show that: For the Ladoping strontium hexaferrite, since the ionic radius of La3+ion is much smaller thanthat of Sr2+ion, which made the symmetrical characteristic change at2b site, resultsin the increasing of coercivity with the increase of La doping. However, La3+ionsubstitution of Sr2+ion make part of Fe~(3+)ion change to Fe~(2+)ion, which lead to theslightly decrease of saturation magnetization. For the Dy doped M-type strontiumhexaferrite, Dy also substitutes for Sr2+ion, but the effect of substitution is weaker,the saturation magnetization and coercivity of Dy doped SrFe_(12)O_(19)is lower than thatof SrFe_(12)O_(19)without Dy doping. For the Co doped M-type strontium hexaferrite,when the content of Co reaches x=0.5, the single phase SrCo_(0.5)Fe_(11.5)O_(19)can besynthesized at1100℃, its saturation magnetization is71.23emu/g, which is close tothe theoretical value of SrFe_(12)O_(19), but the coercivity decrease to2520.7Oe. Thus itcan be seen that Co doping has a great help on the improvement of the saturationmagnetization of SrFe_(12)O_(19).
引文
[1]李荫远，李国栋.铁氧体物理学[M].北京：科学出版社，1974：34-36.
[2] F.Kools, et al. Prodeedings of the Eighth International Conference on Ferrites [C].ICF8, Kyoto,2000.
[3]都有为，铁氧体[M].南京：江苏科学技术出版社，1996，第三章.
[4] H.Kojima [M]. Ferromagnetic Materials, Vol.3, E.P.Wohlfarth,322.
[5] B.T.Hirk, W.R.Buessem [J]. IEEE Transactions on Magnetics,1971,659.
[6]刘亚丕等，永磁材料的发展趋势[J].磁性材料及器件，2003，34：41.
[7]日立金属(Hitachi Metals)产品目录.2003.1.
[8] TDK公司产品目录.2002.2.
[9] Chen N, Yang K, Gu M.Y. Microwave absorption properties of La-substitutedM-type strontium ferrites [J]. Journal of Alloys and Compounds.2010,490(1-2):609-612.
[10]刘先松，钟伟等，稀土La离子取代对M型锶铁氧体的结构和磁性的影响[J].稀有金属材料与工程，2002，31（5）：385-388.
[11]甘树才，洪广言等，镧六方铁氧体LaxBa1-xFe12O19的制备与表征[J].应用化学，2000，17（2）：33-35.
[12] Li Q.L., Zhang C.R., Zhao J.X., et al. Preparation of Barium FerriteMicrotubules and Effect of the La-dope onto the property of Barium FerriteMicrotules [J]. Journal of Inorganic Chemistry.2009,25(2):312-316.
[13] G.Mendoza-Suarez, Magnetic properties of BaFe11.6-2xCoxTixO19particlesproduced by sol-gel and spray-drying [J]. Journal of Magnetism and MagneticMaterials,2001,234:73-79.
[14]王常生等，Co-Ti替代钡铁氧体的磁性研究[J].磁性材料及器件，1999，21（3）：20-24.
[15]宏刚，李发伸，Co-Sn替代钡铁氧体的制备及其磁性[J].甘肃工业大学学报，1994，20（2）：18-21.
[16] Xiaofeng Yang, Qiaoling Li, Jingxian Zhao, Baodong Li, Yongfei Wang,Preparation and magnetic properties of controllable-morphologiesnano-SrFe12O19particles prepared by sol-gel self-propagation synthesis [J].Journal of Alloys and Compounds,2009,475:312-315.
[17] M. Sivakumar; A. Gedanken; Zhong, W.; Du, Y. W.; D. Bhattachreya; Y.Yeshurun; I. Felner. Nanophase formation of strontium hexaferrite fine powderby the sonochemical method using Fe(CO)5[J], Journal of Magnetism andMagnetic Materials,2004,268:95-104.
[18] Fu, Y. P.; Lin, C. H.; Pan, K. Y. Strontium hexaferrite powders prepared by amicrowave-induced combustion process and some of their properties [J], Journalof Alloys and Compounds,2003,349:228-231.
[19] Muhammad Javed Iqbal; Muhammad Naeem Ashiq; Pablo Hernandez-Gomez;Jose Maria Munoz. Synthesis, physical, magnetic and electrical properties ofAl-Ga substituted co-precipitated nanocrystalline strontium hexaferrite [J],Journal of Magnetism and Magnetic Materials,2008,320:881-886.
[20] S. V. Ketov; Yu. D. Yagodkin; A. L. Lebed; Yu. V. Chernopyatova; K.Khlopkov. Journal of Magnetism and Magnetic Materials2006,300: e479.
[21] Z. Zhang, M. Rao, R.M.White, D.E.Laughlin, M.H.Kryder, Barium ferrite thinfilm media with perpendicular c-axis orientation and small grain size [J]. Journalof Applied Physics,2000,87:6370-6372.
[22] S.A.Oliver, S.D.Yoon, I. Kozalin, M.L.Chen, C.Vittoria, Growth andcharacterization of thick oriented barium hexaferrite films on MgO (111)substrates [J]. Applied Physics Letters,2000,76:3612-2614.
[23] F.M.M.Pereira, M.R.P.Santos, R.S.T.M.Sohn, J.S.Almeida, A.M.L.Medeiros,M.M.Costa, A.S.B.Sombra, Magnetic and dielectric properties of the M-typebarium strontium hexaferrite (BaxSr1-xFe12O19) in the RF and microwave (MW)frequency range [J]. Journal of Materials Science: Materials in Electronics,2009,20:408-417.
[24] P. Sharma, R.A. Rocha, S.N. de Medeiros, A. Paesano Jr. Structural andmagnetic studies on barium hexaferrites prepared by mechanical alloying andconventional route [J]. Journal of Alloys and Compounds,2007,443:37–42.
[25] Liu Junliang, Zhang Wei, Guo Cuijing, Zeng Yanwei, Synthesis and magneticproperties of quasi-single domain M-type barium hexaferrite powders via sol-gelauto-combustion: Effects of pH and the ratio of citric acid to metal ions (CA/M)[J]. Journal of Alloys and Compounds,2009,479:863-869.
[26] J.G..Huang, H.R.Zhuang, W.L.Li, Synthesis and characterization of nanocrystalline BaFe12O19powders by low temperature combustion [J]. MaterialsResearch Bulletin,2003,38:149-159.
[27] J.Ding, T.Tsuzuki, P.G.McCormick, Ultrafine BaFe12O19powder synthesised bymechanochemical processing [J]. Journal of Magnetism and Magnetic Materals,1998,177-181:931-932.
[28] T.T.V.Nga; N.P.Duong; T.D.Hien. Synthesis of ultrafine SrLaxFe12-xO19particleswith high coercivity and magnetization by sol-gel method [J], Journal of Alloysand Compounds,2009,475:55-59.
[29] J.Ding, H.Yang, W.F.Miao, P.G.McCormick, R.Street, High coercivity Bahexaferrite prepared by mechanical alloying [J]. Journal of Alloys andCompounds,221:70-73.
[30] A.Gruskova, J.Slama, R.Dosudil, D.Kevicka, V.Jancarik, I.Toth, Influence ofCo-Ti substitution on coercivity in Ba ferrites [J], Journal of Magnetism andMagnetic Materals,2002,242-245:423-425.
[31] S.Yong, I.B.Shum, J.C.Kim, M ssbauer and magnetic properties of Co-Tisubstituted barium hexaferrite nanoparticles [J]. Journal of Applied Physics,2002,91:8465-8467.
[32] G.Turrili, F.Licci, A.Paoluzi, T.Besagni, NiTi substituted hexaferrite for magneticrecording [J]. IEEE Transactions on Magnetics,1998,24:2146-2149.
[33] P.A.Marino-Castellanos, J.C.Somarriba-Jarque, J.Anglada-Rivera, Magnetic andmicrostructural properties of the BaFe(12-(4/3)x)SnxO19ceramic system [J]. PhysicaB: Condensed Matter,2005,362:95-102.
[34] Liu, W. Q.; Sun, H.; Yi, X. F.; Liu, X. C.; Zhang, D. T.; Yue, M.; Zhang, J. X.Coercivity enhancement in Nd-Fe-B sintered permanent magnet by Dynanoparticles doping [J]. Journal of Alloys and Compounds,2010,501:67-69.
[35] Q.He, H.Z.Wang, G.H.Wen, Y.Sun, B.Yao, Formation and properties ofBaxFe3-xO4with spinel structure by mechanochemical reaction of α-Fe2O3andBaCO3[J]. Journal of Alloys and Compounds,2009,486:246-249.
[36] H.Z.Wang, Q.He, G.H.Wen, F.Wang, Z.H.Ding, B.Yao, Study of formationmechanism of barium hexaferrite by sintering curve [J]. Journal of Alloys andCompounds,2010,504:70-75.
[1]李文霞，殷声.低温燃烧合成陶瓷微粉[J].硅酸盐学报.1999，2：71－77.
[2] Arvind Varma and Alexander S. Mukasyan. Combustion Synthesis of AdvancedMaterials: Fundamentals and Applications [J]. Korean J. Chem. Eng.2004，21(2),527-536.
[3]宿新泰,燕青芝,葛昌纯.低温燃烧合成超细陶瓷微粉的最新研究[J].化学进展.2005,17（3）：430-435.
[4] Benjamin J S. Hydriding reactions induced by ball milling [J]. Metal Tran,1970,8(1):29-43
[5] G.B.Schaffer and P.G.Mccormick, Reduction of metal oxides by mechanicalalloying [J]. Applied Physics Letters,1989,55:45-46.
[6]计汉容.固态反应中的机械合金化技术[J].云南冶金,1998,27(2)
[7] Benjamin JS. Fundamentals of Mechanical Alloying [J]. Mater Sci, Forum,1992,(88):1
[8] L.Schults and E.Hellsstern,in sinece and Technology of Rapidly QuenchedAlloys, edited by M.Tenhover,W.L.Johnson,and L.E.Tanner (Mater.Res.Soc.Symp.Proc.80, Pittsburgh,PA,1987), P.3
[9] E.Hellstern and L.Schultz, Progress of amorphization reaction during mechanicalalloying in Fe-Zr [J]. Journal and Applied Physics,1988,63:1408-1413.
[10] D.L.Zhang, T.B.Massalaki and M.R.paruchuri, Metallurgical and MaterialsTransactions A,1994,25:73
[11] T.Fukunaga,M.Utsumi,H.Akatsuka,M.Misana and U.Mizutni, Journal ofNon-Crstalline Solids,1996,205-207:531.
[12] C. C. Koch, J. D. Whittenberge. Mechanical milling/alloying of intermetallics [J].Intermetallics,1996,4:339–355
[13] D. Guzm′an, S. Ordo nez, D. Serafini, P. Rojas, O. Bustos. Effect of the millingenergy on the production and thermal stability of amorphous Mg50Ni50[J].Journal of Alloys and Compounds.2009,471:435-441
[14] H. Zuhailawati, Y. Mahani. Effects of milling time on hardness and electricalconductivity of in situ Cu–NbC composite produced by mechanical alloying [J].Journal of Alloys and Compounds.2009,476:142-146.
[15] FlorinVasiliu L.Diamandescu D.Macovei, C. M. Teodorescu D.Tarabasanu-Mihaila, A. M. Vlaicu V. Parvulescu. Fe-and Eu-doped TiO2Photocatalytical Materials Prepared by High Energy Ball Milling [J]. Topics inCatalysis,2009,52:544–556.
[16] Bensebaa, N; Alleg, S; Loudjani, N, et al. Effect of the milling conditions on theamorphisation of Fe77Cr4P8C11alloy [J]. Annales De Chimie-Science DesMateriaux,2010,35(3):177-186.
[17] Wang, HW; Chyou, SD; Wang, SH, et al. Amorphous phase formation inintermetallic Mg2Ni alloy synthesized by ethanol wet milling [J]. Journal ofAlloys and Compounds.2009,479:330–333.
[18]席生歧.高能球磨固态扩散反应研究[J].材料科学与工艺，[15]2000,18(3):9
[19].丛秋滋《多晶二维X射线衍射》科学出版社1997, p36.
[20]马金鑫，朱国凯.扫描电子显微镜入门[M].北京：科学出版社，1985.
[21]吴刚.材料结构表征及应用[M].北京：化学工业出版社，2009，第六章.
[22]杨沛然. SQUID磁强计简介[J].现代科学仪器，1994,[4]：43-45.
[1] M.Anis-ur-Rehman, G.Asghar, Variation in structural and dielectric properties ofco-precipitated nanoparticles strontium ferrites due to value of pH [J]. Joural ofAlloys and Compounds.2011,509:435-439.
[2] M.H.Sousa, F.A.Tourinho, New electric double-layered magnetic fluids based onCopper, Nickel, and Zinc Ferrite nanostructures [J]. Journal of PhysicalChemistry B2001,105:1168-1175.
[3] S.R.Mekala, J.Ding, Magnetic properties of cobalt ferrite/SiO2nanocomposite [J].Journal of Alloys and Compounds.2000,296:152-156.
[4] S.E.Jacobo, L.Civale, M.A.Blesa, Evolution of the magnetic properties duringthe thermal treatment of barium hexaferrite precursors obtained bycoprecipitation from barium ferrite (VI) solutions [J]. Journal of Magnetism andMagnetic Materials2003,260:37-41.
[5] Y.F.Lu, W.D.Song, Properties of BaFe12O19films prepared by laser depositionwith in situ heating and post annealing [J]. Applied Physics Letters2000,76:490-492.
[6] M.N.Ashiq, M.J.Iqbal, I.H.Gul, Structural, magnetic and dielectric properties ofZr-Cd substituted strontium hexaferrite (SrFe12O19) nanoparticles [J]. Journal ofAlloys and Compounds.2009,487:341-345.
[7] Ali Ghasemi, Vladimir Sepelak, Xiaoxi Liu, Akimitsu Morisako, The role ofcations distribution on magnetic and reflection loss properties of ferromagneticSrFe12-x(Sn0.5Zn0.5)xO19[J]. Journal of Applied Physics,2010,107:09A734.
[8] P.G.Bercoff, C.Herme, S.E.Jacobo, The influence of Nd-Co substitution on themagnetic properties of non-stoichiometric strontium hexaferrite nanoparticles[J]. Journal of Magnetism and Magnetic Materials2009,321:2245-2250.
[9] H.Z.Wang, Q.He, G.H.Wen, F.Wang, Z.H.Ding, B.Yao, Study of formationmechanism of barium hexaferrite by sintering curve [J]. Journal of Alloys andCompounds2010,504:70-75.
[10] H.J.Masterson, J.G.Lunney, M.D.Coey, R.Atkinson, I.W.Salter,P.Papakonstantinou, Thin films of barium ferrite with perpendicular magneticanisotropy produced by laser ablation deposition [J]. Journal of Applied Physics,1993,73:3917-3921
[11] M.E.Koleva, S.Zotova, P.A.Atanasov, R.I.Tomov, C.Ristoscu, V.Nelea,C.Chiritescu, E.Gyorgy, C.Ghica, I.N.Mihailescu, Sr-ferrite thin films grown onsapphire by pulsed laser deposition [J]. Applied Surface Science,2000,168:108-113.
[12] J.Jalli, Y.K.Hong, S.Bae, J.J.Lee, G.S.Abo, A.Lyle, S.H.Gee, T.Mewes, J.C.Sur,S.I.Lee, Growth and characterization of144μm thick barium ferrite singlecrystalline film for microwave device application [J]. Journal of AppliedPhysics,2009,105:07A511.
[13] M.A.Popov, I.V.Zavislyak, G.Srinivasan, Simultaneous observation ofmagnetostatic backward volume waves and surface waves in single crystalbarium ferrite platelets with in-plane easy axis [J]. Journal of Applied Physics,2012,111:023901.
[14] Safia Anjum, M.Shahid Rafique, M.Khaleeq-ur-Rahman, K.Siraj, Arslan Usman,S.I.Hussain, S.Naseem, Investigation of induced parallel magnetic anisotropy atlow deposition temperature in Ba-hexaferrites thin films [J]. Journal ofMagnetism and Magnetic Materials,2012,324:711-716.
[15] Josef Bursik, Ivo Drbohlav, Zdenek Frait, Karel Knizek, Radomir Kuzel, KarelKouril, Oriented SrFe12O19thin films prepared by chemical solution deposition[J]. Journal of Solid State Chemistry,2011,184:3085-3094.
[16] Ali Ghasemi, Magnetic properties of substituted strontium ferrite nanoparticlesand thin films [J]. Journal of Magnetism and Magnetic Materials,2012,324:1375-1380.
[17] S.M.Masoudpanah, S.A.Seyyed Ebrahimi, C.K.Ong, Effect of oxygen pressureon microstructure and magnetic properties of strontium hexaferrite (SrFe12O19)film prepared by pulsed laser deposition [J]. Journal of Magnetism andMagnetic Materials,2012,324:1440-1443.
[18] K. Tsukimura, S. Sasaki, and N. Kimizuka, Jpn. J. Appl. Phys. Part1,1997,vol.36, pp.3609-3612.
[19] M. Senna, Difference in the transformation processes of pressed andvibro-milled γ-Fe2O3to α-Fe2O3[J]. Journal of Applied Physics,1978, vol.49:4580-4582.
[20] M. Zdujic, C. Jovalekic, Lj. Karanovic, M. Mitric, D. Poleti, D. Skala,Mechanochemical treatment of α-Fe2O3powder in air atmosphere [J]. MaterialsScience and Engineering A,1998, vol.245:109-117.
[21] P. R. Johan, De Villiers, Crystal structures of aragonite, strontianite andwitherite [J]. The Americal Mineralogist,1971, vol.56:758-767.
[22] B. Yao, L. Liu, S.E. Liu, B.Z. Ding, W.H. Su, Y. Li, J. Non-Cryst. Solids,2000,vol.277, pp.91-97.
[23] M.L. Trudeau, R. Schulz, D. Dussault, A. Van Neste, Structural changes duringhigh-energy ball milling of iron-based amorphous alloys: is high-energy ballmilling equivalent to a thermal process?[J]. Physical Review Letters,1990,vol.46:99-102.
[24] T. Aboud, B.-Z, Weiss, R. Chaim, Mechanical alloying of the immiscible systemW-Cu [J]. Nanostructured Materials,1995, vol.6:405-408.
[25] Qinghui Yang, Huaiwu Zhang, Yingli Liu, Qiye Wen, Microstructure andmagnetic properties of microwave sintered M-type barium ferrite forapplication in LTCC devices [J]. Materials Letters,2009,63:406-408.
[26] S.Capraro, J.P.Chatelon, M.Le Berre, H.Joisten, T.Rouiller, B.Bayard, D.Barbier,J.J.Rousseau, Journal of Magnetism and Magnetic Materials,2004,272:1805-1806.
[27] S.H.Gee, Y.K.Hong, D.W.Erickson, T.Tanaka, M.H.Park, Ex situ annealingmethod for c-axis oriented barium ferrite thick films [J]. Journal of AppliedPhysics,2003,93:7507-7509.
[28] S.Pignard, H.Vincent, J.P.Senateur, Epitaxial and polycrystalline BaFe12O19thinfilms grown by chemical vapour deposition [J]. Thin Solid Films,1999,350:119-123.
[29] Mitsunori Matsumoto, Akimitsu Morisako, Shigeto Takei, Characteristics ofBa-ferrite thin films for magnetic disk media application [J]. Journal of Alloysand Compounds,2001,326:215-220.
[30] I.Wane, A.Bassudou, F.Cosset, A.Celerier, C.Girault, J.L.Decossas, J.C.Vereille,Thick barium hexaferrite (Ba-M) films prepared by electron-beam evaporationfor microwave application [J]. Journal of Magnetism and Magnetic Materials,2000,211:309-311.
[31] S.A.Oliver, S.D.Yoon, I.Kozulin, M.L.Chen, C.Vittoria, Growth andcharacterization of thick oriented barium hexaferrite films on MgO (111)substrates [J]. Applied Physics Letters,2000,76:3612-3614.
[1] P. Sharrock, Particulate magnetic recording media: A Review [J]. IEEETransactions on Magnetics,1989,25:4374-4389.
[2] H. Kryder. Advances in magneto-optic recording technology [J]. Journal ofMagnetism and Magnetic Materials,1990,83:1-5.
[3] O. Kubo; T. Ido; H. Yokoyama. Properties of Ba ferrite particles forperpendicular magnetic recording media [J]. IEEE Transactions on Magnetics,1982,18:1122-1124.
[4] Yang, X. F.; Li, Q. L.; Zhao, J. X,; Li, B. D.; Wang, Y. F. Preparation andmagnetic properties of controllable-morphologies nano-SrFe12O19particlesprepared by sol-gel self-propagation synthesis [J]. Journal of Alloys andCompounds,2009,475:312-315.
[5] Xu, P.; Han, X. J.; Jiang, J. J.; Wang, X. H.; Li, X. D.; Wen, A. H. Synthesis andcharacterization of novel coralloid polyaniline/BaFe12O19nanocomposites [J].Journal of Physical Chemistry C.2007,111:12603-12608.
[6] R. C. Pullar, M. H. Stacey, M. D. Taylor, A. K. Bhattacharya, Decomposition,shrinkage and evolution with temperature of aligned hexagonal ferrite fibres [J].Acta Materialia,2001,49:4241-4250.
[7] M. Sivakumar; A. Gedanken; Zhong, W.; Du, Y. W.; D. Bhattachreya; Y.Yeshurun; I. Felner. Nanophase formation of strontium hexaferrite fine powderby the sonochemical method using Fe(CO)5[J]. Journal of Magnetism andMagnetic and Materials,2004,268:95-104.
[8] Fu, Y. P.; Lin, C. H.; Pan, K. Y. Strontium hexaferrite powders prepared by amicrowave-induced combustion process and some of their properties [J]. Journalof Alloys and Compouds,2003,349:228-231.
[9] Muhammad Javed Iqbal; Muhammad Naeem Ashiq; Pablo Hernandez-Gomez;Jose Maria Munoz. Synthesis, physical, magnetic and electrical properties ofAl-Ga substituted co-precipitated nanocrystalline strontium hexaferrite [J].Journal of Magnetism and Magnetic Materials,2008,320:881-886.
[10] S. V. Ketov; Yu. D. Yagodkin; A. L. Lebed; Yu. V. Chernopyatova; K.Khlopkov, Journal of Magnetism and Magnetic Materials,2006,300:e479-e481.
[11] Xu, P.; Han, X. J.; Wang, M. J. Synthesis and magnetic properties of BaFe12O19hexaferrite nanoparticles by a reverse microemulsion technique [J]. Journal ofPhysical Chemitry C.2007,111:5866-5870.
[12] S.E.Jacobo, C.Herme, P.G.Bercoff, Influence of the iron content on theformation process of substituted Co-Nd strontium hexaferrite prepared by thecitrate precursor method [J]. Journal of Alloys and Compounds,2010,495:513-515.
[13] Muhammad Naeem Ashiq, Muhammad Javed Iqbal, Iftikhar Hussain Gul,Effect of Al-Cr doping on the structural, magnetic and dielectric properties ofstrontium hexaferrite nanomaterials [J]. Journal of Magnetism and MagneticMaterials,2011,323:259-263.
[14] D.Seifert; J.Toper; F.Langenhorst; J.-M.Le Breton; H.Chiron; L.Lechevallier.Synthesis and magnetic properties of La-substituted M-type Sr hexaferrite [J].Journal of Magnetism and Magnetic Materials,2009,321:4045-4051.
[15] T.T.V.Nga; N.P.Duong; T.D.Hien. Synthesis of ultrafine SrLaxFe12-xO19particleswith high coercivity and magnetization by sol-gel method [J]. Journal of Alloysand Compounds,2009,475:55-59.
[16] Feng Hu, Lucia Fernandez-Garcia, Xian-Song Liu, De-Ru Zhu, Marta Suarez,Jose Luis Menendez, A strong magneto-optical activity in rare-earth La3+substituted M-type strontium ferrites [J]. Journal of Applied Physics,2011,109:113906.
[17] Muhammad Javed Iqbal; Muhammad Naeem Ashiq; Pablo Hernandez Gomez.Effect of doping of Zr-Zn binary mixtures on structural, electrical and magneticproperties of Sr-hexaferrite nanoparticles [J]. Journal of Alloys and Compounds,2009,478:736-740.
[18] Liu, W. Q.; Sun, H.; Yi, X. F.; Liu, X. C.; Zhang, D. T.; Yue, M.; Zhang, J. X.Coercivity enhancement in Nd-Fe-B sintered permanent magnet by Dynanoparticles doping [J]. Journal of Alloys and Compounds,2010,501:67-69.
[19] Bertaut E F, Deschamps A, Pauthenet R, Pickart S, J. Physique Rad.20(1959)404.
[20] S. Wang, J. Ding, Y. Shi, Y. J. Chen, High coercivity in mechanically alloyedBaFe10Al2O19[J]. Journal of Magnetism and Magnetic Materials,2000,219:206-212.
[21] Mingquan Liu, Xiangqian Shen, Fuzhan Song, Jun Xiang, Xianfeng Meng,Microstructure and magnetic properties of electrospun one-dimensionalAl3+-substituted SrFe12O19nanofibers [J]. Journal of Solid State Chemistry,2011,184:871-876.
[22] H.Z.Wang, Q.He, G.H.Wen, F.Wang, Z.H.Ding, B.Yao, Study of formationmechanism of barium hexaferrite by sintering curve [J]. Journal of Alloys andCompounds,2010,504:70-75.
[23] M.Mozaffari, A.Arab, M.H.Yousefi, J.Amighian, Preparation and investigationof magnetic properties of MnNiTi-substituted strontium hexaferritenanoparticles [J]. Journal of Magnetism and Magnetic Materials,2010,322:2670-2674.
[24] J.Kreisel; G.Lucazeau; H.Vincent. Raman study of substituted barium ferritesingle crystals, BaFe12-2xMexCoxO19(Me=Ir, Ti)[J]. Journal of RamanSpectroscopy,1999,30:115-120.
[25] Zhao, W.Y.; Wei, P.; Wu, X.Y.; Wang, W.; Zhang, Q.J. Lattice vibrationcharacterization and magnetic properties of M-type barium hexaferrite withexcessive iron [J]. Journal of Applied Physics,2008,103:063902.
[26] M.W.Pieper; F.Kools; A.Morel. Phys Rev. B65(2002)184402.
[27] Kurikka V. P. M. Shafi, Israel Felner, Y. Mastai, Aharon Gedanken, Olympicring formation from newly prepared barium hexaferrite nanoparticle suspension[J]. Journal of Physical Chemistry B1999,103:3358-3360.
[28] L. Zhang, G. C. Papaefthymiou, J. Y. Ying, Synthesis and properties of γ-Fe2O3nanoclusters within mesoporous aluminosilicate matrices [J]. Journal ofPhysical Chemistry B2001,105:7414-7423.
[29] A.J.Rondinone, A.C.S.Samia, A.J.Zhang, Superparamagnetic relaxation andmagnetic anisotropy energy distribution in CoFe2O4spinel ferritenanocrystallites [J]. Journal of Physical Chemistry B1999,103:6876-6880.
[30]李荫远，李国栋.铁氧体物理学[M].北京：科学出版社，1978，第四章.
[1] S.A.Oliver, S.D.Yoon, I.Kozulin, M.L.Chen, C.Vittoria, Growth andcharacterization of thick oriented barium hexaferrite films on MgO (111)substrates [J]. Applied Physics Letters,2000,76:3612-3614.
[2] A.Vijayalakshmi, N.S.Gajbhiye, Magnetic properties of single-domain SrFe12O19particles synthesized by citrate precursor technique [J]. Journal of AppliedPhysics,1998,83:400-406.
[3] N Kishan Reddy, V.N.Mulay, Magnetic properties of W-type ferrites [J].Materials Chemistry and Physics,2002,76:75-77.
[4] P.Hemandez-Gomez, P.G.Bercoff, O.Alejos, C.Torres, J.M.Munoz, C.deFrancisco, J.I.Iniguez, H.R.Bertorello, Magnetic disaccommodation in Srhexagonal ferrites with X-phase (2SrO·15Fe2O3) initial composition [J].Physica B: Condensed Matter,2002,320:267-269.
[5] M.Jean, V.Nachbaur, J.Bran, J.Le Breton, Synthesis and characterization ofSrFe12O19powder obtained by hydrothermal process [J]. Journal of Alloys andCompounds,2010,496:306-312.
[6] L.Qiao, L.You, J.Zheng, L.Jiang, J.Sheng, The magnetic properties of strontiumhexaferrites with La-Cu substitution prepared by SHS method [J]. Journal ofMagnetism and Magnetic Materials,2007,318:74-78.
[7] T.Kikuchi, T.Nakamura, T.Yamasaki, M.Nakanishi, T.Fujii, J.Takada, Y.Ikeda,Magnetic properties of La-Co substituted M-type strontium hexaferritesprepared by polymerizable complex method [J]. Journal of Magnetism andMagnetic Materials,2010,322:2381-2385.
[8] Z.Wang, L.Zhong, J.Lv, H.Qian, Y.Zheng, Y.Fang, M.Jin, J.Xu,Microwave-assisted synthesis of SrFe12O19hexaferrites [J]. Journal ofMagnetism and Magnetic Materials,2010,322:2782-2785.
[9] X.S.Liu, W.Zhong, S.Yang, Z.Yu, B.X.Gu, Y.W.Du, Structure and magneticproperties of La3+-substituted strontium hexaferrite particles prepared by sol-gelmethod [J]. Physica Status Solidi A,2002,193:314-319.
[10] X.S.Liu, P.Hernandez-Gomez, Y.X.Deng, K.Huang, X.B.Xu, S.X.Qiu, D.Zhou,Analysis of magnetic disaccommodation in La3+-Co2+-substituted strontiumferrites [J]. Journal of Magnetism and Magnetic Materials,2009,321:2421-2424.
[11] X.S.Liu, W.Zhong, S.Yang, Z.Yu, B.X.Gu, Y.W.Du, Influences of La3+substitution on the structure and magnetic properties of M-type strontium ferrite[J]. Journal of Magnetism and Magnetic Materials,2002,238:207-214.
[12]刘先松，钟伟，顾本喜等.稀土La3+离子取代对M型锶铁氧体的结构和磁性的影响[J].稀有金属材料与工程，2002，31（5）：385-388.
[13] George Litsardakis, Ioannis Manolakis, Anagnostis C.Stergiou, et al. NewDy-substituted Ba hexaferrites with high coercivity [J]. IEEE Transactions onMagnetics,2008,44:4222-4224.
[14] Sonal Singhai, A.N.Garg, Kailash Chandra, Evolution of the magneticproperties during the thermal treatment of nanosize BaMFe11O19(M=Fe, Co, Niand Al) obtained through aerosol route [J]. Journal of Magnetism and MagneticMaterials,2005,285:193-198.
[15]李汶霞，殷声，低温燃烧合成陶瓷微粉[J].硅酸盐学报，1999，27（1）：71-78.
[16] X.S.Liu, W.Zhong, S.Yang, Z.Yu, B.X.Gu, Y.W.Du, Influences of La3+substitution on the structure and magnetic properties of M-type strontium ferrite[J]. Journal of Magnetism and Magnetic Materials,2002,238:207-214.
[17] Liu, W. Q.; Sun, H.; Yi, X. F.; Liu, X. C.; Zhang, D. T.; Yue, M.; Zhang, J. X.Coercivity enhancement in Nd-Fe-B sintered permanent magnet by Dynanoparticles doping [J]. Journal of Alloys and Compounds,2010,501:67-69.
[18]都有为，铁氧体[M].南京：江苏科学技术出版社，1996，第三章.
[19] H.Kojima [M]. Ferromagnetic Materials, Vol.3, E.P.Wohlfarth,322.
