Spin, charge and lattice couplings in Cu-deficient oxysulphide BiOCu0.94S.
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.
Department of Physics and Center for Neutron Beam Applications, National Central University, Jhongli 32001, Taiwan.
Sunil K
SK
Karna
Chin-Wei
CW
Wang
Chun-Ming
CM
Wu
Chien-Kang
CK
Hsu
Daniel
D
Hsu
Chih-Jen
CJ
Wang
Wen-Hsien
WH
Li
Raman
R
Sankar
Fang-Cheng
FC
Chou