Regularities in temperature, magnetic field and pressure effect on the resistive properties of magnetic semiconductors

Abstract

The influence of hydrostatic pressure, magnetic field and temperature on resistivity behaviour of bulk and film samples La 0.9Mn 1.1O 3 and La 0.56Ca 0.24Mn 1.2O 3 at action of magnetic field and temperature has been analysed. It is established that the maximum of magnetoresistive and the revealed baroresistive, magnetobaroresistive effects coincide at the same temperature T pp. This temperature is equal to the “metal-semiconductor” phase transition temperature T ms. “Cooling” and “heating” effects of pressure and magnetic field have been revealed. A mutual correspondence of T– P– H (6.2 K, 1 kbar, 2.7 kOe) influence on polycrystalline sample La 0.9Mn 1.1O 3 resistivity has been determined. The linear change of T ms( P) and T ms( H) in La 0.9Mn 1.1O 3, La 0.56Ca 0.24Mn 1.2O 3 resistivity have been found. An importance of the regularities of elastic-deforming correspondence of T– H– P influence on magnetic, resistivity properties, phase transitions and effects was elucidated and explained. An alternating influence of T– H– P and its role in resistivity has been pointed. A correlation between structural, elastic and resistive properties is specified.