Magnetoimpedance Response of a Double-Exchange Metallic Ferromagnet La0.80Sr0.20MnO3

In this paper, we investigate the magnetoimpedance (MI) response of a double-exchange ferromagnet La_0.80Sr_0.20MnO₃ using a non-contact method with the help of a copper strip coil and an impedance analyzer over a wide frequency range (1 MHz-2.0 GHz). In recent years, MI of metallic soft ferromagnetic alloys was measured by passing radio frequency (RF) currents through a sample and varying an applied magnetic field to obtain the magnetoresistance (ΔR/R₀) and magnetoreactance (ΔX /X₀). The strip coil method has never been used before to measure MI for bulk metallic systems. In this method, RF current flows through the circumference of the strip coil, instead of the sample, creating an RF magnetic field along the axial direction. Thus, this RF field excites the magnetization in the sample. The MI features observed in this paper have been explained in terms of both the magnetization rotation and ferromagnetic resonance. We also analyze the role of the skin effect in our MI response.