Metamagnetic properties in Mn0.7Mg0.3Fe2O4 ferrite

The paper deals with metamagnetic behaviour of the MnMg ferrites with stoichiometric composition Mn0.7Mg0.3Fe2O4 and is focused to structural nature of found effects. The results are a part of the materials research concerning the relationship between the types of the change from antiferomagnetic (AFM) state to ferrimagnetic (FM) state under the influence of temperature at selected magnetic field. In lower applied field under the critical value of strength Hac the increase in magnetic induction B with temperature is attributed to transition from Yafet-Kittel model to Néel's two-sublattices one. Various evaluation methods, such as e.g. thermo-magnetic analysis, magnetic Barkhausen noise analysis, and X-ray diffraction were used for obtaining experimental data. Magnetic Barkhausen noise analysis showed that mainly the domain-wall motion processes take place in the examined MnMg system. •The metamagnetic transition from antiferromagnetic to the ferrimagnetic state in the MnMg ferrite was studied.•The increase in induction with increase in temperature implies, that spin ordering changes from Yafet-Kittel to Néel type.•The magnetic Barkhausen noise method appears as an interesting method of evaluation of phase transition in this material.•One class of MnMg ferrites can become attractive in the cloak systems shielding an object from a dc and/or ac magnetic field.