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Detailed electron paramagnetic resonance (EPR) studies on a single crystal of Gd 3+doped Van Vleck compound EuAlO 3 , potentially a phosphorescent/ luminescent/laser material, with the Gd 3+ ion substituting for the Eu 3+ 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 Eu 3+ ion in a low symmetry environment. The asymmetry exhibited by the variation of the Gd 3+ 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 1 4 b , 3 4 b , 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 Gd 3+ EPR linewidth is interpreted to be due to the "life-time" broadening, caused by dynamical exchange and dipolar interactions between the impurity Gd 3+ ions and the host Eu 3+ ions. P.A.C.S. Classification: 76.30 Kg

Vanadium pentoxide films are synthesized by pyrolysis. The optimum conditions of heat treatment providing for the effective use of films as gas sensors are determined. The sensitivity of the films to different gaseous media (vapors of ethanol, methanol, and argon) is investigated by measuring the electrical conductivity in the temperature range 300-800 K.