La0.67Ca0.33MnO3 film by simple spin coating: large anisotropic magnetoresistance in the vicinity of room–temperature

Polycrystalline La 0.67 Ca 0.33 MnO 3 films were fabricated by spin–coating, exhibiting strong structural anisotropy, along with excellent anisotropic magnetoresistance (AMR) and temperature coefficient of magnetoresistance (TCM) properties. These films show potential as materials for angle sensors in consumer electronics. The crystallinity and interface matching of La 0.67 Ca 0.33 MnO 3 films are closely linked to sintering conditions. Enhanced crystallization promotes better grain orientation, grain boundary connectivity, and lattice anisotropy, ultimately leading to improved physical properties. That is, the optimized sintering temperature of 1100 °C led to best grain boundary connectivity, resulting in −19.8 % AMR at 1T and 26.7 % TCM at 0.1T near room temperature (≈270 K). A comparative analysis of temperature, magnetic field, and performance demonstrates that the sample achieves the best AMR performance (0–1 T magnetic field, response temperature close to room temperature) compared to existing literatures. Additionally, significant magnetic anisotropy was observed, with the magnetic susceptibility anisotropy enhanced by a factor of three near the Curie temperature. Curie–Weiss fitting showed that films with optimal crystallinity exhibited significant differences between the in–plane and out–of–plane effective magnetic moments, while films with poorer crystallinity showed minimal differences, indicating that structural anisotropy underlies the anisotropy in magnetic properties.