EPR AND OPTICAL SPECTROSCOPY OF CR3+ DOPED CAYALO4

EPR and optical measurements have been carried out on Cr3+ doped CaYAl O4 at 1.6 K, 16 K and 300 K. Q-band measurements revealed a strong, as ymmetric EPR line close to g similar or equal to 2 for B parallel to c , together with three weak finestructure lines corresponding to tetrag onal symmetry. The R(1) line of Cr3+ has an inhomogeneous broadened li newidth of about 100 cm(-1) at 16 K but a homogeneous width of less th an 10 cm(-1), the measurement of which was monochromator slit width li mited. The large inhomogeneous broadening of the optical and EPR spect ra are attributed to the compositional disorder of Ca2+ and Y3+ in the host lattice.