The remnant ferromagnetism in the Cu1−xAgxIr2S4 system

In this paper, we have investigated the magnetic properties of spinel sulphide materials Cu1−xAgxIr2S4(0≤x≤0.15). Based on the measurement of magnetization and specific heat, the weak remnant ferromagnetism is found in this system. The remnant ferromagnetism, which coexists with paramagnetism and diamagnetism, is enhanced with the increase of Ag content. Theoretical calculation in magnetization and specific heat also supports the present experimental observation. The remnant ferromagnetism observed here may be related to either non-dimerized Ir4+ ions or defects in this system.