Magnetization of FeBO3 by microwave pumping

Changes in the magnetic moment of crystalline FeBO3 when an antiferromagnet ic resonance is excited in it are studied. This done using a SQUID magnetom eter in combination with a microwave spectrometer. At temperatures T > 15 K a reduction in the total magnetic moment of the sample is observed when an antiferromagnetic resonance is excited in it. At liquid helium temperature s, an induced rise in the sample magnetic moment was observed. This type of magnetization of the sample can be explained qualitatively if it is assume d that under antiferromagnetic resonance excitation conditions, magnetoelas tic modes with high wave numbers are excited along with magnons. Efficient excitation of magnetoelastic modes under antiferromagnetic resonance condit ions is confirmed by the experimental observation of a size effect in thin, high quality single crystal slabs of FeBO3. (C) 1999 American Institute of Physics. [S1063-7761(99)02503-2].