Oxygen Content and Thermomagnetic Properties in Cu1-ξMgξFe₂O₄

Lattice constants and thermomagnetic properties of Cu 1-ξ Mg ξ Fe 2 O 4 were studied in detail with changing the quenching temperature and with employing a high oxygen pressure furnace. It was confirmed for CuFe 2 O 4 that the previously reported inverse-normal change is not due to the simple thermal effect but due to the change in the degree of oxidation, or, due to the generation of Cu 1+ . This is not the case for MgFe 2 O 4 and it was shown experimentally and theoretically that the reasonable representation of the activation energy \(\) as a function of x , (Mg x Fe 1- x ) [Mg 1- x Fe 1+ x ]O 4 , is not \({=}₀-₁x\) but \({=}₀+₁x-₂x²\).