Magnetically tunable rf wave absorption in polycrystalline   La0.67Ba0.33MnO3
  We investigated temperature and magnetic field dependent radio-frequency electromagnetic absorption in La0.67Ba0.33MnO3 by monitoring changes in resonance frequency (fr) and current (II) through a LC resonant circuit powered by an integrated chip oscillator. The ferromagnetic to paramagnetic transition at Tc in zero external 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 delfr/fr and 23% in delI/I around Tc under H = 0.1 T that can be exploited for low magnetic field sensors and other applications. 
V. B. Naik and R. Mahendiran