MOSSBAUER-EFFECT AND DIELECTRIC-CONSTANT OF A YIG SINGLE-CRYSTAL AND POSSIBILITY OF A LOW-TEMPERATURE STRUCTURAL TRANSITION

Mossbauer effect and dielectric constant measurements were performed with single crystal specimens of Y3Fe5O12 (YIG), to obtain information as to a possible phase transition at 125 K, where the first order magnetoelectric effect appears. Mossbauer spectra for various conditions were compared, and the results indicated that there was no detectable difference between the spectra above and below the supposed transition point and between those cooled to 77 K with and without electric field. This means that the lattice distortion at the phase transition, if any, is too small to affect the Mossbauer spectrum or the disappearance of the center of symmetry was due to some other mechanism than structural phase transition. The results of dielectric measurements was also negative for the existence of a structural phase transition.