Influence of random substitution on magnetocaloric effect in a spinel ferrite

Influence of random substitution of non magnetic ions on magnetocaloric effect is studied on manganese zinc ferrites from the view points 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 non toxic elements. (C) 2009 Elsevier B.V. All rights reserved.