Enhanced anisotropic magnetoresistance in La0.7–xSmxCa0.3MnO3 through lattice distortion control for magnetic sensors

Perovskite manganese oxides have recently attracted significant interest due to the strong coupling between their charge, orbital, spin, and lattice degrees of freedom. These materials exhibit prominent anisotropic magnetoresistance (AMR), positioning them as potential candidates for magnetic sensors technologies. However, their low AMR values under moderate magnetic fields remain a challenge for practical implementation. In this work, we enhanced AMR performance by optimizing the lattice structure through A-sites ionic ratio adjustments. La 0.7– x Sm x Ca 0.3 MnO 3 ( x  = 0.0–0.06) was synthesized using a non-aqueous sol-gel method, with Sm 3+ and Sm 2+ substituting La 3+ and Ca 2+ , inducing significant lattice modulation. Structural analysis revealed that the Jahn-Teller distortion reached its peak at x  = 0.02, achieving an AMR value of 43 %, the highest reported so far. Magnetic measurements showed that higher Sm doping weakened the double-exchange interaction, leading to a decrease in curie temperature and ferromagnetic phase fraction. This study offers an effective strategy for improving AMR performance in perovskite materials under moderate magnetic fields, enabling their practical use in magnetic sensing devices.