Department of Physics, Chung-Yuan Christian University, Jhongli, 32023 Taiwan.
Inorg Chem. 2010 Apr 5;49(7):3297-304. doi: 10.1021/ic9022823.
The interplay between the crystalline and magnetic structures of a 4% Cr-doped Bi(0.37)Ca(0.63)Mn(0.96)Cr(0.04)O(2.99) has been investigated by alternating current (ac) magnetic susceptibility, electrical resistivity, and neutron diffraction measurements. The compound crystallizes into a monoclinic P2(1)/m symmetry. A Jahn-Teller distortion occurs at 280 K. The thermal behavior of charge transport may be described by a three-dimensional variable range hopping conduction. Strong interplay between the localized magnetic electrons and the itinerant electrons are clearly revealed as the localization length increases by 20% when the Mn spins become ordered below 85 K. Short range magnetic correlations persist up to 160 K. The collinear magnetic structure can be viewed as consisting of ferromagnetic spin-trimers antiferromagnetically embedded in a ferromagnetic environment. Cr-doping reduces the charge ordering temperature and the magnetic ordering temperature. It nevertheless introduces long-range ferromagnetism.
通过交流（ac）磁导率、电阻率和中子衍射测量研究了 4% Cr 掺杂的 Bi(0.37)Ca(0.63)Mn(0.96)Cr(0.04)O(2.99)的晶体和磁结构之间的相互作用。该化合物结晶为单斜 P2(1)/m 对称。在 280 K 时发生 Jahn-Teller 畸变。电荷输运的热行为可以用三维变程跳跃传导来描述。当 Mn 自旋在 85 K 以下有序时，局域磁电子和巡游电子之间的强烈相互作用导致局域化长度增加 20%，这一点得到了清晰的揭示。短程磁关联一直持续到 160 K。共线磁结构可以看作是由铁磁自旋三聚体反铁磁嵌入在铁磁环境中组成的。Cr 掺杂降低了电荷有序温度和磁有序温度。然而，它引入了长程铁磁性。
