Elastic-strain mechanisms for the influence of temperature, magnetic field, and pressure on the resistive and magnetic properties of magnetic semiconductors

Abstract

An analysis is made of the results of studies of the variation of the resistivity of a bulk polycrystalline sample of La0.56Ca0.24Mn1.2O3 under the influence of temperature (T), pressure (P), and magnetic field (H) and a study of the variation of the magnetostriction in single-crystal LaMnO3 as a function of T and H. It is found that the peaks of the magnetoresistive, baroresistive, and baromagnetoresistive effects occur at the same temperature, which is independent of magnetic field and pressure and corresponds to the temperature Tms of the metal–semiconductor phase transition in the absence of magnetic field and pressure. “Cooling” and “heating” effects of pressure and magnetic field are detected, and an equivalency of the influence of T, P, and H on the resistivity of the polycrystalline sample and of T and H on the magnetostriction of the single-crystal LaMnO3 is observed. The linearity of the shifts of the Tms(P) and Tms(H) peaks in the resistive properties of La0.56Ca0.24Mn1.2O3 is demonstrated and ...