Structure-Dependent Magnetoresistance in the Zn0.1Cd0.9GeAs2 + 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 Zn0.1Cd0.9GeAs2 matrix and MnAs clusters. A record high negative magnetoresistance of ~74% is formed near a pressure-induced structural transition (P≈ 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. [ABSTRACT FROM AUTHOR]