Magnetocaloric characterization of materials

The magnetocaloric effect manifests itself as a change in temperature of a magnetic material following the variation of an applied magnetic field. This effect constitutes the basis for the development of important applications such as magnetic refrigeration and, in general, thermomagnetic energy conversion technologies. Accurate and reliable characterization of the magnetocaloric effect is crucial for identifying and selecting the most promising materials and for realistic design of refrigerant machines. This chapter provides a comprehensive and critical review of the methods and experimental setups developed for measuring the magnetocaloric effect. It offers an in-depth discussion and analysis of both indirect magnetometric and calorimetric methods and direct methods, along with detailed descriptions of the experimental setups adopted. Each technique is examined to highlight its primary advantages and potential issues, providing a practical guide for obtaining accurate magnetocaloric characterizations of materials. The chapter also addresses the measurement of the effect across first-order transitions, emphasizing the importance of proper measurement protocols. Special conditions, such as rapid field changes or low-mass samples, are considered carefully, as they can provide new insights into material properties or simulate real application conditions. Additionally, some recent advanced experimental techniques are presented, which are capable of simultaneously measuring different physical properties of materials or coupled multicaloric effects.