Paramagnetic Metal-Antiferromagnetic Insulator Transition of λ-BETS_2Fe_xGa_<1-x>Cl_4 System
Paramagnetic Metal-Antiferromagnetic Insulator Transition of λ-BETS_2Fe_xGa_<1-x>Cl_4 System
复制标题
λ-BETS_2Fe_xGa_<1-x>Cl_4体系的顺磁金属-反铁磁绝缘体转变
DOI：
10.1143/jpsj.81.053601
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发表时间：
2012
影响因子：
1.7
通讯作者：
H.Kobayashi
中科院分区：
文献类型：
--
作者：
H.Akiba;H.Sugawara;K.Nobori;K.Shimada;N.Tajima;Y.Nishio;K.Kajita;B.Zhou;A.Kobayashi;H.Kobayashi
准二维有机导体λ-BETS2FeCl4[BETS = bis（乙烯二硫）四烯丙烯]在零磁场下以8.3 K的转变温度由顺磁性金属（PM）转变为反铁磁性绝缘体（AFI）。为了研究这种PM-AFI相变的机理，我们通过测量混合晶体λ- bets2fexga1 - xcl4在低至0.2 K时的比热，研究了Fe三维自旋含量对AFI基态的依赖。Fe三维自旋密度的增加增强了由π自旋反铁磁（AF）有序引起的内部磁场。证实了Fe三维自旋为这一神秘的PM-AFI相变提供了有利条件。我们认为这种相变源于π -d相互作用引入的磁各向异性，π -d相互作用抑制了π自旋系统的低维涨落。
The quasi-two-dimensional organic conductor λ-BETS2FeCl4[BETS = bis(ethylenedithio) tetraselenafulvalene] transforms from a paramagnetic metal (PM) to an antiferromagnetic insulator (AFI) at a transition temperatureTMIof 8.3 K under a zero magnetic field. To investigate the mechanism of this PM–AFI phase transition, we studied the Fe 3dspin content dependence of the AFI ground state by measuring the specific heat of the mixed crystal λ-BETS2FexGa1-xCl4at temperatures as low as 0.2 K. The increasing Fe 3dspin density enhances the internal magnetic field caused by π spin antiferromagnetic (AF) ordering. It was confirmed that the Fe 3dspin provides favorable conditions for this mysterious PM–AFI phase transition. We propose that this phase transition originates from the magnetic anisotropy introduced by the π–dinteraction, which suppresses the low-dimensional fluctuation in the π spin system.