Influence of random substitution on magnetocaloric effect in a spinel ferrite

摘要

Influence of random substitution of nonmagnetic ions on magnetocaloric effect is studied on manganese zinc ferrites from the viewpoints of Griffiths effects and frustration effects. The obtained results show that these side effects are insignificant at the ferrimagnetic transition in the range of zinc content below 70%. Consequently, the ferrite can keep a large magnetocaloric effect even when the transition temperature is lowered to a half of the original. This finding indicates that the nonmagnetic substitution is useful in adjusting the working temperature, if we utilize popular magnets such as ferrites with high Curie temperatures for the refrigerant consisting ubiquitous and nontoxic elements.