Zn Doping Effect on Magnetic Properties of Zn_xCd_1-xCr₂S₄ Systems by High-Temperature Series Expansions

The effect of Zn doping on the magnetic properties of CdCr₂S₄ systems is studied by mean field theory and high-temperature series expansion (HTSE). The nearest neighbouring and the next-neighbouring super-exchange interactions J₁(x) and J₂(x) are evaluated for the spinel system Zn_xCd_1-xCr₂S₄ in the range 0≤x≤1. The intra-planar and the inter-planar interactions are deduced. The HTSE combined with the Pade approximant method (PA) is applied to the spinel system Zn_xCd_1-xCr₂S₄. The magnetic phase diagram, i.e. T_C versus dilution x, is obtained. The critical exponents associated with the magnetic susceptibility γ and the correlation length ν are deduced. The obtained theoretical results are in agreement with the experimental data obtained by magnetic measurements.