Department of Physics and Center for Neutron Beam Applications, National Central University, Jhongli 32001, Taiwan.
J Phys Condens Matter. 2012 Jul 4;24(26):266004. doi: 10.1088/0953-8984/24/26/266004. Epub 2012 Jun 7.
The electrical and magnetic properties of slightly Cu-deficient BiOCu(0.94)S are investigated using neutron diffraction, ac magnetic susceptibility, magnetization and electrical resistivity measurements. The Cu spins order in a ferromagnetic arrangement below T(C) = 250 K. An antiferromagnetic component develops below 180 K when the crystalline unit cell experiences a sharp thermal contraction upon cooling, resulting in a canted ferromagnetic spin arrangement at low temperatures. In the magnetically ordered state the electrical transport can be described using three-dimensional variable range hopping conduction. An applied magnetic field can effectively reduce the hopping barrier. Spin-charge couplings are clearly revealed when the resistivity departs from the hopping conduction and begins to increase with increasing temperatures above 250 K where the Cu spins become disordered.
采用中子衍射、交流磁化率、磁化强度和电阻率测量研究了略缺铜的 BiOCu(0.94)S 的电性和磁性。在 250 K 以下，Cu 自旋以铁磁方式排列。当冷却时，晶体单元经历急剧热收缩，在 180 K 以下会产生反铁磁分量，导致低温下的倾斜铁磁自旋排列。在磁有序状态下，电输运可以用三维变程跳跃传导来描述。施加磁场可以有效地降低跳跃势垒。当电阻率偏离跳跃传导并随温度升高而升高，超过 250 K 时 Cu 自旋变得无序时，自旋-电荷耦合就会明显显现。
