Strain modulated magnetization and colossal resistivity of epitaxial La_2/3Ca_1/3MnO₃ film on BaTiO₃ substrate

A sharp drop in resistance and a magnetization anomaly have been observed in La_2/3Ca_1/3MnO₃ film in zero magnetic field at the BaTiO₃ substrate structural phase transition temperature, due to the substrate clamping/strain effect, which is confirmed by Raman scattering. However, the anomalies for both resistance and magnetization were eliminated by a strong external magnetic field. These phenomena indicate that strain can cause colossal resistance and a change in magnetization which resembles the magnetic field effect. The interplay of the external forces (strain and magnetic field) is a good demonstration of the strong coupling between spin and lattice in colossal magnetoresistance materials.