Spin-glass-like behavior and electrical transport properties of Cr_7(Se_(1-x)Te_x)_8

摘要

The magnetic and electrical transport behaviors of Cr_7Se_(1-x)Te_x)_8 compounds are investigated in detail. Spin-glass-like behavior is observed, which results from the spin frustration due to the competition between ferromagnetic and antiferromagnetic interactions. As Se is substituted by Te, a minimum of resistivity is observed in temperature dependence of resistivity and the temperature T_(min) corresponding to the minimum increases with Te concentration. Hopping conductivity in terms of variable range-hopping is used to describe the electrical transport behavior below T_(min). The resistivity of these compounds is sensitive to the external magnetic field, which shifts the magnetic ordering temperature T_(MO) to higher temperature and T_(min) to lower temperature. The resistivity at the magnetic field becomes smaller, compared to the zero-field value, resulting in a negative magnetoresistance.