Magnetically tunable rf wave absorption in polycrystalline La 0.67 Ba0.33 MnO3

Abstract

We investigated temperature and magnetic field dependent radio-frequency electromagnetic absorption in La0.67 Ba0.33 MnO 3 by monitoring changes in resonance frequency (fr) and current (I) through a LC resonant circuit powered by an integrated chip oscillator. The ferromagnetic to paramagnetic transition at TC in zero magnetic field is accompanied by an abrupt increase in fr and I and they are tunable by small external magnetic field. We observed fractional changes as much as 46% in Δ fr / fr and 23% in ΔI/I around TC under μ0 H=0.1 T that can be exploited for low-magnetic field sensors and other applications. © 2009 American Institute of Physics.