Transport properties of Y3Fe5O12 garnet crystals

The temperature dependence of electrical resistivity ρ and thermopower θ is studied for a series of Y₃Fe₅O₁₂ (YIG) garnet single crystals with different levels of optical and structural quality. The effect of some technology-related impurities on the value of ρ is discussed. It is shown for the first time that the experimental data on the absorption coefficient and electrical resistivity can be interpreted based on a single physical parameter, namely, the intensity ratio of coherent and incoherent X-ray scattering (K/nk). This ratio characterizes the fraction of conduction electrons in a given sample. The results are discussed with due regard for the nonequivalence of the planes of the {110} and {111} types. The additional details of the charge-transfer mechanism are established for the (111)-oriented YIG samples. It is suggested that the ρ values could be characterized in terms of nk or nk/K.