ELECTRON-PARAMAGNETIC RESONANCE INVESTIGATION OF PHASE-TRANSITION IN RBCDF3

An EPR investigation of Cr3+ center associated nearest-neighbor Cd2+ vacancy in RbCdF3 has been carried out in the temperature range from 300 to 77 K. The field-direction dependence of the spectrum in the (001) plane at 77 K evidently shows the alternate rotations of the fluorine octahedra around the tetragonal c-axis. This behavior should originate from the distortion of nearest-neighbor fluorine ion caused by Cd2+ vacancy. The results indicate that this center is a sensitive probe to detect the rotations of octahedra caused by the phase transition for multidomain sample and is capable of determining the crystal structure in the low symmetry phase conclusively. © 1979, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.