Structure and physical properties of ceramics in a section of the system Mg-Cu-Fe-O

The concentration dependences of the crystal lattice parameter and the Curie temperature of the magnetic ceramic, obtained in air at a calcination temperature of 1100°C from charges with the composition (1–x)MgFe₂O₄+x(0.5 CuO × 1.25 Fe₂O₃), where 0x1, were studied. The dependences of the magnetic parameters of the hysteresis loop as well as the resistivity on the composition of the charge were investigated. The single-phase ceramic, having the structure of spinel, is formed for x < 0.5, and in samples with x > 0.5 a tetragonal phase and -Fe₂O₃ are present. The maximum squareness ratio of the hysteresis loop (SHL) is observed in the region x=0.1–0.4. The region of high values of the squareness ratio is also the region of solid solutions containing defects, when -Fe₂O₃ quasiparticles, having the structure of imperfect spinel, are present in the solution.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 84–86, December, 1990.