Atlas Copco AB, Sweden

Abstract

Reducing the loss of temperature coefficient of resistivity (TCR) in the magnetic field and increasing the low−field magnetoresistance (MR) are two crucial issues to be solved for large scale practical applications of perovskite materials. In this work, polycrystalline La0.67−ySmyCa0.33MnO3 (shortly LCMO:Smy, where y = 0.02, 0.04, 0.06, 0.08) ceramics were synthesized via optimized sol−gel technology. Colossal intrinsic MR up to 71 % was achieved in produced composites by applying only the magnetic field of 1 T. Lattice distortion was found to be a key factor governing the intrinsic MR response. In presence of magnetic field, the most unperturbed TCR up to 24 %·K−1 was attained in LCMO:Sm0.06 system, where the TCR−loss was only 1 %·K−1. This was explained by the opposite external field direction with respect to Jahn−Teller distortion, which enabled one to solve the problem of large attenuation of TCR under the magnetic field. These findings reveal great potential of the LCMO:Sm0.06 ceramic for applications in infrared bolometers and magnetic recording devices in complex electromagnetic environments.