Polycrystalline La0.66Gd0.04Ca0.3MnO3 for magnetic-response applications: concurrent anisotropic magnetoresistance and magneto-transport under a low magnetic field

Abstract

Polycrystalline manganites with outstanding anisotropic magnetoresistance and temperature coefficient of magnetization have great potential for application in magnetic sensors. Recent studies have shown that altering the ion occupation ratio would induce Jahn–Teller distortion and affect the spin–orbital coupling effect, consequently enhancing anisotropic magnetoresistance and temperature coefficient of magnetization. In this study, single-phase polycrystalline La_0.7−xGd_xCa_0.3MnO₃ ceramics were fabricated via a simple nonaqueous sol–gel technique. The optimal Gd doping concentration induced the strongest Jahn–Teller distortion, as was confirmed through the Curie–Weiss behavior of the ceramics. Finally, these ceramics demonstrated the relatively large anisotropic magnetoresistance and temperature coefficient of magnetization (−30% and −28.1%/K, respectively) values under a low magnetic field of 1 T. The enhanced anisotropic magnetoresistance properties were derived from the spin–orbital coupling effect as demonstrated by the classical transport model.