This paper summarizes the recent investigations of photoinduced effects in magnetic materials. To date it has been shown that the uniaxial anisotropy, strain, linear dichroism, coercive force and initial permeability can be modified by infrared radiation. The theory interpreting the coercive force and permeability experiments differs from the model used to describe the first three effects and is not discussed here. The first three effects can be interpreted fairly well in terms of a model which has single Fe2+ ions preferentially occupying inequivalent octahedral sites. It is shown that with polarized light more than half of the available Fe2+ ions can be selectively moved among specific types of sites. Irradiation with unpolarized light essentially leads to a distribution appropriate for thermal equilibrium at the temperature of the sample.
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