MAGNETO-OPTICAL INVESTIGATION OF ELECTRON TRANSITIONS IN Ga, In AND Sc SUBSTITUTED YIG

Magnetic circular dichroism (MCD) of Y3Fe5-xMxO12 (where M is a diamagnetic ion) is investigated as a function of x, in the spectral range 8 000 to 20 100 cm-1. A sharp decrease is found for 0.8 ≤ x ≤ 1.0, which depends on substituent-ion site occupancy and on site-assignement of the electron transitions. This effect is illustrated in detail in the case of Ga substitution, and explained in the framework of the concepts of sublattice magnetization contributions to MCD and sublattice magnetization behaviour in randomly diluted iron garnets

Contribution of spontaneous polarization and its fluctuations to refraction of light in ferroelectrics

The expressions for the spontaneous polar contribution delta n (i) (s) to the principal values of the refractive index due to the quadratic electro-optic effect in ferroelectrics have been considered within the phenomenological approach taking into account the polarization fluctuations. A method has been proposed for calculating the magnitude and temperature dependence of the root-mean-square fluctuations of the polarization (short-range local polar order) P (sh) = aEuroP (fl) (2) aEuro parts per thousand(1/2) below the ferroelectric transition temperature T (c) from temperature changes in the spontaneous polar contribution delta n (i) (s) (T) if the average spontaneous polarization P (s) = aEuroPaEuro parts per thousand characterizing the long-range order is determined from independent measurements (for example, from dielectric hysteresis loops). For the case of isotropic fluctuations, the proposed method has made it possible to calculate P (sh) and P (s) only from refractometric measurements. It has been shown that, upon interferometric measurements, the method developed in this work allows calculating P (sh) and P (s) directly from the measured temperature and electric-field changes in the relative optical path (the specific optical retardation) of the light

Optical Study of the Electronic Structure and Magnetic Ordering in a weak Ferromagnet FeBO3

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