Time Dependent Magnetic Phenomena in Dilute Ising Systems Fe_1-xMg_xCl₂

Abstract

Dilute Ising systems Fe_1-xMg_xCl₂ are a random mixtures of FeCl₂ and MgCl₂ both crystallizing in the CdCl₂ structure with a hexagonal layered lattice. A pure FeCl₂ has ferromagnetic c planes stacked antiferromagnetically along the c axis. There exists fairly strong uniaxial anisotropy parallel to the c axis.[1] Recently these dilute systems have attracted considerable attention because of their interesting magnetic properties inherent in a typical Ising-like random magnet with short range interaction. In the region where x is beyond the site percoration threshold (x_c=0.5) of the triangular net for spin sites, the system exhibits Ising spin glass behavior at low temperatures.[2] For x<0.5, the coexistence of spin glass and antiferromagnetic ordering has been observed.[3] Then, focusing on these characteristic concentration ranges below and above x_c, we will show the results of the dynamical properties of the remanent magnetization of this Ising system through the measurement of the Faraday effect.