The s-d mixing model, in which electron-photon coupling was taken into account, was employed to study the effect of optical irradiation on the moment of a magnetic impurity embedded in a nonmagnetic base. The local magnetic moment was calculated self-consistently by employing the Green-function technique. There exists notable photomagnetic effect, while the energy level configuration meets the resonant-absorption condition and the effective on-site energy of local electrons approaches the Fermi energy Ef. The change of local moment primarily originates from the transition between a d-like local state and a p-like local (extended) state. The mechanism of photomagnetic effect of a magnetic impurity is that the optical irradiation breaks the original balance of electron distribution under Column interaction (Hubbard repulsion) via the change of local energy-level position and the decrease of its lifetime and hence results in the variation of local magnetic moment.

Under inclined magnetic field, the propagation characteristics of magnetostatic waves (MSWs) for a double-layered waveguided structure are theoretically studied by using surface permeability method. A new concept called & mode interlamination coupling' is proposed by analysis of mode spectrum, which develops a generalized understanding of the MSWs propagating in a layered structure. A similar treatment can be applied to the situation of multi-layered structure under inclined field. In addition, the dispersion relation and delay characteristics of coupled mode in two different YIG films are studied by numerical analogue at inclination angle from 5 to 20

The noncollinear interaction between guided optical waves and magnetostatic waves under inclined bias magnetic field is studied in detail. The diffraction efficiency (DE) and the mode-conversion efficiency (MCE) of guided optical waves with magnetostatic forward volume waves in the bismuth-doped yttriu-miron-garnet (Bi-doped YIG) waveguide are calculated numerically. The calculation results indicate that the DE and the MCE are different in physical conception and the DE is not equal to the MCE in magnitude under inclined bias magnetic field. The DE may be greatly increased by using an appropriately inclined bias magnetic field, which has been experimentally confirmed in a pure YIG waveguide. By using an inclined bias magnetic field and the Bi-doped YIG waveguide, under the phase-matching conditions, the maximum DE can come up to 79.5% or more.

This paper first considers the effects of multielectron interaction, L-S interaction and the weak crystal-field on the 4f3 ground state of Nd3+ ion in the paramagnetic medium NdF3; then, further takes account of the splitting of the crystal-field ground levels caused by both the effective superexchange field Hv and the applied field He, and calculates quantitatively the temperature dependence of the magnetic susceptibility x in NdF3. For the splitting of 4f25d excited state of Nd3+ ion in NdFs, the paper investigates the effect of the strong crystal-field on the 5d electrons. Using the model of three-level transition, the specific Faraday rotation θF, the Verdet constant V, and their temperature dependence, which originate from the electronic transitions between the electron configurations 4f3 and 4f25d, are calculated quantitatively. The theoretical calculations show that the superexchange interaction between Nd3+ ions has an important effect on the magneto-optical properties in NdF3, and both V-1 and x-1 are linearly dependent on T in the temperature range 70 K<T<300 K. The theory is in good agreement with the experimental results.

This paper first considers the effects of L-S interaction and the crystal field on both the 4Fground state and the 5d excited state of Pr 3+ ions in the paramagnetic material PrF3, and further takes account of the splitting of the crystal-field ground levels caused by the effective superexchange field H Y and the applied field He, and then, using the model of double tramition with the splitting of the ground stale, cabdates quantitatively the magnetic susceptibility x, specific Faraday rotation θF. Verdet constant V. and their temperature dependence in PrF3. The theoretical calculations show that the magneto-optical effect and its temperature dependence in PrF3 are closely related to the superexchange interaction between Pr3+ ions. V-1 and X-1 are linearly dependent of T in the temperature range of [10K≤T≤300K and independent of T in the low-temperature regime. The theory is in agreement with the experimental results.

We first consider the effects of the crystal field on both the 4f ground state and the 5d excited state of a Ce3+ ion in the paramagnetic medium CeF3, and further take account of the splitting of the crystalfield ground-state levels caused by the effective superexchange field Hv and the applied field He; then, with a model of a double transition that includes ground-state splitting, we calculate quantitatively the specific Faraday rotation θF, the Verdet constant V, the magnetic susceptibility X, and their temperature dependences in CeF3. Theoretical calculations show that the magneto-optical effect and its temperature dependence in CeF3 are closely related to the superexchange interaction between Ce3+ ions. V-1 is linearly dependent on T and V/X=-18353(1+63.01/T) in the temperature range 60<T≤300K. The theory is in good agreement with the experimental results.

In ferrimagnetic media, besides originating from the splitting of the excited state resulting from the spin-orbit interaction, magneto-optical effects also arise from the splitting of the ground state caused by the superexchange interaction and applied field. A theoretical calculation according to this view shows that the Faraday rotation 0 depends linearly on sublattice magnetization Mi (i=1,2,..., l) in both the low-temperature and high-temperature regimes for the medium with high Curie temperature, while in the normal-temperature regime, 0 depends nonlinearly on each Mi and T. The theory is in good agreement with experimental results.

Having used the classical electromagnetic field theory and combined it with the effective-field conception, in this paper we show that: 1) The real part θ of Faraday rotation φ in any kind of the magneto-optical (MO) material can be expressed in the fundamental form of θ=VLHi. 2) The differences in the MO properties of the different kinds of the MO media mainly result from both the characteristics and the size of their effective field Hi and especially, the different temperature properties in various media are discussed. 3) The relationship between the real part θ and the imaginary part ψ of φ can be described by the effective extinction coefficient η*. 4) The other MO properties are predicted. It is proved that the effective field Hv, which is concerned in both the spin-orbital interaction and the exchange interaction (or the indirect exchange interaction) in media, can be expressed in the form of Hv=vM (or E1=1viMi). Some theoretical results are verified by experiments.

In ferromagnetic media, besides originating from the splitting of the excited state resulting from the spin-orbit interaction, magneto-optical effects also arise from the splitting of the ground state caused by both the exchange interaction and the applied field. In view of the standpoint mentioned above, it is shown by calculation that the Faraday rotation 0 depends linearly on magnetization M in both the regions of T<T, (Curie temperature) and of high temperature for the medium with high T c, but nonlinearly on M and Tin the usual temperature region between the above two regions.

In some paramagnetic media, the effective field Hi, which includes an effective exchange field and an applied field, can cause a splitting of the ground level. In the temperature region T>Tc (Tc is the Curie temperature), there are certain probability distributions of electrons on two energy levels due to ground-state splitting. This induces the ground level for a double transition. It is shown that there are several temperature behaviors for the magneto-optical Faraday effect in paramagnetic media. If the applied field is not too large, the ratio of the Verdet constant to the magnetic susceptibility is V/x=A (1+BT) in some media, or V/x=A (1+B/T) in other media. It is also indicated that both the real part θ' and imaginary part θ" of the Faraday rotation are proportional to the effective field Hl, and show similar temperature behaviors beyond the region of optical absorption.