Obtaining of magnetic soft ferrites by creating frustrated magnetic structure in them

Abstract
Samples of system CuGa_xAl_xFe_2-28O₄ (x 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7) have been sintered and temperature-dependences of their spontaneous magnetization σs coercive force H_c parallel Z_a and perpendicular Z_i magnetostrictions have been investigated. Based on the experimental data it has been concluded that in the compounds with x ≥ 0.5 there is a transition from paramagnetic state to spin glass phase, and at still lower temperatures, a transition to frustrated magnetic phase is observed. It has been found that the coercive force of the ferrires with frustated magnetic structure is an order of magnitude smaller than the coercive force of the ferrites which have ferrimagnetic arrangement. Magnetostriction study has shown that in given ferrites anisotropic magnetostriction has a quite small value. Therefore it has been established that in the samples with a frustrated magnetic structure magnetic anisotropy is small. On this base we suggest a new method of obtaining ferrites with a small coercive force bu creating in them a frustrated magnetic structure.