A review and new perspectives for the magnetocaloric effect: New materials and local heating and cooling inside the human body

• The recent progress in magnetocaloric effect (MCE) studies.
• Existing and perspective methods of MCE measurements.
• Investigation of MCE parameters in dynamic mode and in low fields.
• Novel medical applications of MCE: local hyperthermia and drug delivering.

Nowadays, the magnetocaloric effect (MCE) is considered to be one of the most important fundamental thermodynamic effects to be employed in various technological applications. At present researchers focus mainly on environmentally-friendly magnetic materials and their applications in heating, refrigeration and magnetic energy conversion technologies. However, one must also pay attention to the increasing number of medical applications of the MCE, as e.g. controllable delivery and release of drugs and biomedical substances to defined locations in the human body, and applications of magnetic hyperthermia (cancer treatment). The first method demands local cooling of thermo-sensitive polymers in the body and the second induces local heating by a magnetic mechanism. In the first part of this article the recent progress in magnetocalorics (mainly on materials) is reviewed and the possibilities to increase the effect, e.g. by studying the interactions of magnetic and structural subsystems of magnetic materials in the vicinity of magnetic phase transitions and critical points, are outlined. To determine such and other important phenomena in the MCE, dynamic measurements have been developed. In the second part of the article the applications of the MCE in new methods, developed for applications in medical fields, as briefly mentioned above, are introduced and discussed. It is clear that a comprehensive overview on all important developments cannot be given here. Therefore, only the most important works are cited with a focus on important developments of Russian research. We ask those authors, who have contributed to the MCE and stay unmentioned in this review article, for their understanding.