门电压诱导的单分子磁体磁滞效应
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摘要
基于率方程研究了温差驱动的单分子磁体中,门电压诱导的磁滞效应。当门电压从某一负值缓慢地增加到某一正值再从该正值返回到负值时,分子磁体磁化强度对门电压的响应曲线不重合,而是一条闭合磁滞回线。这种磁滞效应是分子磁体的宏观量子效应,只出现在低温下,可以从分子态占据概率对门电压的依赖来解释。此外,还讨论了温度、铁磁电极极化率以及交换作用对磁滞回线所围面积的影响。
The gate voltage induced hysteresis in single molecule magnet with temperature difference is investigated by using the rate equation.When the gate voltage slowly increases from negative value to positive value and reaches a certain value,and then returns its initial value,the response curve of molecule magnet magnetization to gate voltage is not coincide and forms a hysteresis loop.The hysteresis loop in single molecule magnet is a macroscopic quantum effect and appears only at low temperature and can be explained by dependence of the occupation probability of molecule state on the gate voltage.Moreover,the effects of the temperature,polarization of the ferromagnetic electrode and spin exchange interaction on the area of hysteresis loops is discussed.
The gate voltage induced hysteresis in single molecule magnet with temperature difference is investigated by using the rate equation.When the gate voltage slowly increases from negative value to positive value and reaches a certain value,and then returns its initial value,the response curve of molecule magnet magnetization to gate voltage is not coincide and forms a hysteresis loop.The hysteresis loop in single molecule magnet is a macroscopic quantum effect and appears only at low temperature and can be explained by dependence of the occupation probability of molecule state on the gate voltage.Moreover,the effects of the temperature,polarization of the ferromagnetic electrode and spin exchange interaction on the area of hysteresis loops is discussed.
引文
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[2]Blundell S J,Pratt F L.Topical Review:Organic and Molecular Magnets[J].J Phys:Condens Matter,2004,16:R771-R828.DOI:10.1088/0953-8984/16/24/R03.
[3]Joachim C,Gimzewski J K,Aviram A.Electronics Using Hybrid-Molecular and Mono-Molecular Devices[J].Nature London,2000,408:541-548.DOI:10.1038/35046000.
[4]Timm C,Elste F.Spin Amplification,Reading,and Writing in Transport Through Anisotropic Magnetic Molecules[J].Phys Rev B,2006,73:235304.DOI:10.1103/PhysRevB.73.235304.
[5]Heersche H B,Groot Z D,Folk J A,et al.Electron Transport through Single Mn12 Molecular Magnets[J].Phys Rev Lett,2006,96:206801.DOI:10.1103/PhysRevLett.96:206801.
[6]Jo M H,Grose J E,Baheti K,et al.Signatures of Molecular Magnetism in Single-Molecule Transport Spectroscopy[J].Nano Lett,2006,6(9):2014-2020.DOI:10.1021/nl061212i.
[7]Romeike C,Wegewijs M R,Schoeller H.Spin Quantum Tunneling in Single Molecular Magnets:Fingerprints in Transport Spectroscopy of Current and Noise[J].Phys Rev Lett,2006,96:196805.DOI:10.1103/PhysRevLett.96.196805.
[8]Elste F,Timm C.Cotunneling and Nonequilibrium Magnetization in Magnetic Molecular Monolayers[J].Phys Rev B,2007,75:195341.DOI:10.1103/PhysRevB.75.195341.
[9]赵丽芝,聂一行.单分子磁体耦合铁磁电极的量子输运[J].山西大学学报:自然科学版,2009,32(1):41-44.DOI:10.13451/j.cnki.shanxi.univ(nat.sci.).2009.01.013.
[10]Misiorny M,Barnasa J.Spin Polarized Transport Through a Single-Molecule Magnet:Current-Induced Magnetic Switching[J].Phys Rev B,2007,76:054448.DOI:10.1103/PhysRevB.76.054448.
[11]Lu H Z,Zhou B,Shen S Q.Spin-bias Driven Magnetization Reversal and Nondestructive Detection in a Single Molecular Magnet[J].Phys Rev B,2009,79::174419.DOI:10.1103/PhysRevB.79.174419.
[12]Zhang Z,Jiang L,Wang R,et al.Thermoelectric-Induced Spin Currents in Single-Molecule Magnet Tunnel Junction[J].Appl Phys Lett,2010,97:242101.DOI:10.1063/1.3525571.
[13]徐卫平,牛鹏斌,聂一行.人工分子磁体中的热电特性研究[J].山西大学学报:自然科学版,2013,36(4):569-573.DOI:10.13451/j.cnki.shanxi.univ(nat.sci.).2013.04.019.
[14]Zhang Z,Jiang L,Wang R,et al.Manipulating the Spin of Single-Molecule Magnet by Thermal Spin-Transfer Torque[J].Appl Phys Lett,2011,99:133110.DOI:10.1063/1.3644476.
[15]Li Shujing,Zhang Yuying,Xu Weiping,et al.Gate Voltage Induced Magnetization Reversal and Tunneling Anisotropic Magnetoresistance in Single Molecular Magnet with Temperature Gradient[J].Chin Phys Lett,2016,33(6):067203.DOI:10.1088/0256-307X/33/6/067203.