Magnetization studies of(GeTe)1−x(MnTe)xpseudobinary alloys

Abstract

We present measurements and analysis of the magnetic properties of the degenerate magnetic semiconductor ${\left(\mathrm{GeTe}\right)}_{1-x}{\left(\mathrm{MnTe}\right)}_x$ for $0<x<\mathrm{}0.5\mathrm{}$. The measurements were made in fields of up to 55 kOe over the temperature range 1-350 °K. The results fall into two parts. For $x<\mathrm{}0.15\mathrm{}$, the properties are well explained by a simple Ruderman-Kittel-Kasuya-Yosida (RKKY) theory with an exchange constant between the manganese and the free carriers of 0.9±0.09 eV, in excellent agreement with a previously reported independent determination from transport properties. For $x>\mathrm{}0.20\mathrm{}$, the experimental results deviate strongly from the predictions of this simple model and exhibit some striking properties which we believe to be intrinsic. Suggestions are offered for the causes of these deviations.