Structure-dependent magnetoresistance in the Zn$_{0.1}$Cd$_{0.9}$GeAs$_2$ + MnAs hybrid nanocomposite

The effect of high pressure on electron transport and on the field dependence of the transverse magnetoresistance has been studied in a hybrid nanocomposite based on the Zn$_{0.1}$Cd$_{0.9}$GeAs$_2$ matrix and MnAs clusters. A record high negative magnetoresistance of $\sim74\%$ is formed near a pressure-induced structural transition ($P\approx 3.5$ GPa). The considered scattering mechanisms include both the contribution from MnAs clusters at relatively low pressures (up to $0.7$ GPa) and spin-dependent scattering by localized magnetic moments in the Mn-substituted structure of the matrix in the region of the structural transition. The presence of the positive magnetoresistance region associated with the two-band transport model in the high-pressure phase, as well as the large negative magnetoresistance, is described in the framework of the semiempirical Khosla–Fischer expression.