Ferromagnetic antiresonance in La0.7Ba0.3MnO3 traced out by temperature variation

Using the phenomenon of ferromagnetic antiresonance (FMAR) in ceramic samples of La0.67Ba0.33MnO3 at 10 GHz, we report a large magneto-impedance MI=Rs(Hl) -Rs(H⊥)/Rs(Hl), where Rs is the microwave surface resistance and H the applied field. The MI reaches 30% at a field of 30 mT near room temperature. The FMAR also lets us measure M(T) by following Rs as a function of T and H. © 1997 American Institute of Physics.