A microwave power absorption characterization of YMnO3

We report on the effects of temperature and dc magnetic field on the microwave power absorption measurements at X-band (8.8–9.8 GHz), in powder samples of YMnO3 (YM). Two techniques are used: magnetically modulated microwave absorption spectroscopy (MAMMAS) and low-field microwave absorption spectroscopy (LFMAS). The measurements were performed in the 77–520 K temperature range. MAMMAS response showed distinctive features associated with microwave absorption by magnetic and electric dipoles; at low and high temperatures, the paramagnetic and dielectric absorptions of microwave are dominant, respectively. The profiles obtained by plotting the slope vs. temperature of the LFMAS line, while cooling or heating, are similar to those detected by the MAMMAS technique. We conclude that both measurements are a manifestation of the same response to electromagnetic absorption, in which the same physical processes take place.