Antiferromagnetic semiconductor La0.6Ba0.15Ca0.15Ag0.1MnO3 perovskite with strong magnetocaloric and giant magnetoresistance effects

Abstract

The structural, electrical, magnetic, and electronic properties of La_0.6Ca_0.15Ba_0.15Ag_0.1MnO₃ (LBCAMO) were investigated experimentally and via density functional theory (DFT). Synthesized via the sol–gel method, this compound exhibits non-uniform nanospherical particles (∼40 nm) and an insulator-metal transition at 75 K, accompanied by a colossal magnetoresistance of 99% at 2 T. Magnetic studies reveal a sharp antiferromagnetic (AFM)-to-ferromagnetic (FM) transition at 156 K and a second transition from FM-to-paramagnetic (PM) at 241 K. A giant magnetocaloric effect ΔS_M = 11.22 J kg⁻¹ K⁻¹ is observed at 6 T. DFT calculations reveal that, at low temperature, the system stabilizes in an A-type antiferromagnetic ground state with a Mott insulating gap of approximately 1.2 eV. The interplay of lattice, spin, and charge degrees of freedom underpins the observed transitions, positioning LBCAMO as a promising candidate for spintronics and magnetic cooling.