Abstract
The X-band ESR spectrum of vanadium-doped alpha cristobalite AlPO4 has been observed at room temperature. The spectrum, attributed to V4+ in a distorted tetrahedral site, can be described by a spin Hamiltonian of axial symmetry. The Hamiltonian parameters are: g/sub ///=1.9168, gperpendicular to =1.9835, mod A/sub /// mod =188*10-4 cm-1, mod Aperpendicular to mod =75*10-4 cm-1. The wavefunction of the ground state is of the dx2-y2 type.