摘要
利用传统高温固相反应法制备了钙钛矿钴氧化物Pr_(2-x)Tb_xCoMnO_6(x=0.00,0.05,0.10)系列多晶样品,通过样品的XRD谱线、磁化强度随温度、外加磁场的变化曲线(M-T、M-H)等对样品的晶体结构和磁性进行了研究.结果表明:系列样品Pr_(2-x)Tb_xCoMnO_6(x=0.00,0.05,0.10)呈现良好的单相性,空间点群为P2_1/n;由于Co~(2+)与Mn~(4+)之间的铁磁超交换相互作用和少量无序的Co~(3+)与Mn~(3+)之间的铁磁超交换相互作用,3个样品均出现两个铁磁转变点(T_(C1)和T_(C2)),观察到系列样品存在类Griffiths相,温度T>T_G则为纯顺磁态;在T_(C2)-T_G之间属于顺磁-铁磁共存状态;在低温区(T A series of polycrystalline samples of perovskite cobalt oxide Pr_(2-x)Tb_xCoMnO_6(x=0.00,0.05,0.10) were prepared by traditional high-temperature solid-state reaction. The XRD spectra, magnetization curves and variation curve of applied magnetic field(M-T, M-H) with temperature were measured to study the crystal structure and magnetic properties of the sample. The results show that the series of samples Pr_(2-x)Tb_xCoMnO_6(x=0.00,0.05,0.10) exhibited good single phase. The spatial point group was P2_1/n. Due to the ferromagnetic super-exchange interaction between Co~(2+) and Mn~(4+) and a small amount of disordered ferromagnetic super-exchange interaction between Co~(3+) and Mn~(3+), two ferromagnetic transition points appeared in all the three samples. It is observed that there is a Griffiths-like phase in the series of samples. When temperature T was higher than T_G, it showed pure paramagnetic state. When temperature was between T_(C2)-T_G, it showed paramagnetic-ferromagnetic coexistence state. At low temperature(Tced the process of pure paramagnetic state, paramagnetic-ferromagnetic coexistence state and ferromagnetic-antiferromagnetic competition.
引文
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