Magnetoimpedance effect at various temperatures for manganite La0.7Ca0.3MnO3−δ

In the present work, the AC magnetoimpedance effect in La0.7Ca0.3MnO3−δ at various temperatures are investigated. The peak of the metal–insulator transition occurs in the temperature dependence of impedance. Negative magnetoimpedance effect in the La0.7Ca0.3MnO3−δ is obtained at frequencies f≤10 MHz. In the magnetoimpedance effect of manganites, the magnetic field not only decreases the permeability μt, but also reduces the resistivity ρ by aligning the local spins and varying the transfer integral tij. The AC magnetoimpedance participated by the DC colossal magnetoresistance (CMR) in manganites, should be connected with the combined effects of double exchange interaction, electron–phonon coupling and skin effect.