Localization of conduction electrons and the magnetic properties of the molecular metals β″-(BEDT-TTF)4NH4[M(C2O4)3] · DMF (M = Cr3+, Fe3+)
Localization of conduction electrons and the magnetic properties of the molecular metals β″-(BEDT-TTF)4NH4[M(C2O4)3] · DMF (M = Cr3+, Fe3+)
复制标题
传导电子的局域化和金属分子β″-(BEDT-TTF)4NH4[M(C2O4)3] · DMF (M = Cr3+, Fe3+)的磁性
DOI：
10.1134/s1063776106010146
复制
发表时间：
2006
影响因子：
1.1
通讯作者：
Y. Tanimoto
中科院分区：
文献类型：
--
作者：
R. Morgunov;R. Shibaeva;E. Yagubskii;T. Kato;Y. Tanimoto
用电子顺磁共振研究了准二维有机金属β“-(BEDT-TTf)4NH4[M(C2O4)3]·DMF的导电性有机层间的草酸盐络合物，确定了这些金属络合物、传导电子和非平衡晶格缺陷对磁化率的贡献。磁化率和EPR谱线形状与温度关系的分析表明，在含Cr3+离子的晶体中，导电电子在T<；20K时部分局域化。局域化区域的大小接近单个BEDT-TTF分子的大小。在室温下长期存放，随着非平衡缺陷的消失，局域效应减弱。在传导电子局域化的同时，发现在T<；20K时，Cr3+离子之间出现了弱的反铁磁相互作用，当Fe3+离子取代Cr3+离子时，这种作用消失了。
Quasi-two-dimensional organic metals β″-(BEDT-TTF)4NH4[M(C2O4)3] · DMF containing the oxalate complexes of Cr3+ or Fe3+ ions between the conducting organic layers of the BEDT-TTF molecules are studied by EPR spectroscopy, and the contributions of these metallic complexes, conduction electrons, and non-equilibrium lattice defects to the magnetic susceptibility are determined. An analysis of the temperature dependence of the magnetic susceptibility and the EPR line shape has revealed partial localization of conduction electrons at T < 20 K in the crystals with Cr3+ ions. The size of the localization region is close to the size of an individual BEDT-TTF molecule. The localization effect weakens as nonequilibrium defects disappear during long-term storage at room temperature. The localization of conduction electrons is found to be accompanied by the appearance of weak antiferromagnetic interaction between the Cr3+ ions at T < 20 K, which disappears when Fe3+ ions substitute for Cr3+ ions.