Magnetodielectric response in 0.36BiScO₃-0.64PbTiO ₃/La_0.7Sr_0.3MnO₃ thin films and the corresponding model modifications

Dielectric relaxation and magnetodielectric (MD) effects were observed in 0.36BiScO₃-0.64PbTiO₃/La_0.7Sr _0.3MnO₃ thin films. The universal dielectric response and distribution of relaxation time modifications were introduced into the Maxwell-Wagner (MW) model. Based on modified MW model, the negative MD response at low frequencies was attributed to magnetostriction of La_0.7Sr _0.3MnO₃, while the large positive response at high frequencies mainly to the magnetoresistance of La_0.7Sr _0.3MnO₃, and these two factors canceled each other out at intermediate frequencies. Moreover, a giant room temperature MD response of 9.5 was observed, and the linear MD response at 52 kHz was ascribed to the linear magnetoresistance effects.