Nearest and next nearest neighbor exchange interaction between magnetic ions in II–VI semimagnetic semiconductors

Abstract

The Mn-Mn exchange constants, which have been determined accurately in the last few years using various experimental methods, are analysed versus Mn composition, x, and interionic distance in II–VI semimagnetic semiconductors. The theoretical expression of the mean exchange constant, J 1, between nearest neighbor is given versus x. Theory and experimental values are in agreement in the whole composition range. The exchange interaction between next nearest neighbor, J 2, obtained from the study of the high magnetic fields magnetization versus x up to x = 0.11 for Cd 1- x Mn x Te and Zn 1- x Mn x Te are reported. Neglecting longer range interactions, the Curie-Weiss temperature, θ c, of telluride compounds is calculated from J 1 and J 2 versus Mn composition. The result of the calculation is compared to the data available in the literature. For high x, a curvature of θ c versus x which is negative for Zn 1- x Mn xTe and positive for Cd 1- x Mn x Te is observed.