Abstract

Detailed electron paramagnetic resonance (EPR) studies on a single crystal of Gd3+-doped Van-Vleck compound EuAlO3, potentially a phosphorescent/luminescent/laser material, with the Gd3+ ion substituting for the Eu3+ ion, were carried out at X-band (9.2 GHz) over the 77–400 K temperature range. They provide new physical results on magnetic properties of the Eu3+ ion in a low symmetry environment. The asymmetry exhibited by the variation of the Gd3+ EPR line positions for the orientations of the external magnetic field about the Z and X magnetic axes in the ZX plane was ascribed to the existence of low, monoclinic, site symmetry, as revealed by the significant values of the spin-Hamiltonian (SH) parameters and , estimated by fitting all the observed EPR line positions at room temperature for the orientation of the magnetic field in the magnetic ZX plane using a least-square fitting procedure. The temperature dependence of the Gd3+ EPR linewidth is interpreted to be due to the “life-time” broadening, caused by dynamical exchange and dipolar interactions between the impurity Gd3+ ions and the host Eu3+ ions.