Pressure-induced magnetic transformations in Cd3As2+MnAs hybrid composite

Considerable interest to magnetism of MnAs both in bulk or in the form of epitaxial films is stimulated by its applications as a magnetocaloric material and in spintronic devices. Since the MnAs films deposited on GaAs reproduce well a magnetic transformation related to alpha-beta magnetostructural transition that occurs in bulk MnAs, this first-order phase transition occurs through a phase coexistence over a wide temperature range. Here, we considered the same magnetostructural transition in a bulk hybrid structure based on micrometer-scaled MnAs inclusions embedded into the Cd3As2 matrix. In particular, the effect of high pressure and magnetic fields on the ferromagnetic transition temperature, T-C, in a composite Cd3As2 + 30 mol. % MnAs has been studied. We found that at ambient pressure, the transition from alpha-MnAs to beta-MnAs is accompanied by the absence of thermal hysteresis of magnetization, implying a phase coexistence regime. The hysteresis width does not markedly increase even at pressures about P = 0.35 GPa, and displacement of T-C occurs with a rate of dT(C)/dP ~ -91.42 K/GPa. In the temperature region of the alpha-beta phase coexistence, a local peak at T = 283 K and P = 1 GPa is observed, which is associated with an antiferromagnetic order of MnAs inclusions. Direct measurements of isothermal magnetization vs pressure indicate both the stabilization of the ferromagnetic hexagonal alpha phase at P < P-max and the development of an orthorhombic antiferromagnetic long-range order, which propagate up to 5 GPa.& nbsp;Published under an exclusive license by AIP Publishing.