Fe3+ electron paramagnetic resonance study of a YCaAlO4 single crystal: Study of substitutional disorder
X(~9.7 GHz) and Q(~35.6) band EPR measurements on a single crystal of Fe3+ -doped YCaAlO4 are performed to investigate the effect of substitutional disorder upon introduction of Fe3+ ions in this crystal. A model is proposed which takes into account the distribution of the orientations of the magnetic z axes of the various Fe3+ ions in a Gaussian manner about the c axis of the crystal, accounting satisfactorily for the observed angular variation of the Fe3+ EPR linewidth due to substitutional disorder. The parameters of this model serve to characterize the disorder. In addition, the Fe3+ spin Hamilton parameters were estimated from EPR line positions at 4.2, 77, and 295 K. In particular, the Fe3+ zero-field splitting parameter b02 was found to have a rather large value, of ~35 GHz for an inorganic host crystal.