Electrical properties and enhanced low-field magnetoresistance of Mn2O3-added La0.7Ca0.3MnO3 ceramics

Abstract

Perovskite La1-xCaxMnO3 (LCMO) has attracted extensive attention due to its unique physical properties, such as its colossal magnetoresistance, charge ordering, and metal-insulation transition, and its potential applications in optoelectronics, infrared detection, and magnetism sensors. However, the low-field magnetoresistance (LFMR) of LCMO requires a low excitation magnetic field, and the actual magnetoresistance (MR) at room temperature still does not meet the application requirements. LCMO combined with a second material with different magnetic properties may improve the LFMR. In this study, the LFMR was improved by compounding La0.7Ca0.3MnO3 with Mn2O3 to create (LCMO)1-x: (Mn2O3)x (x = 0–0.16) composites. The diffusion at the grain boundaries between the two phases changes the Mn3+/Mn4+ ratio, increases the resistivity of the composites, decreases the temperature coefficient of resistivity, and causes the MR to first increase and then decrease. For x = 0.08, MR increases from 52.18% to 56.82% at a relatively low field of 1 T. Such attempts could facilitate the potential applications of the LCMO-based systems.