Thermal Hysteresis Due to the Structural Phase Transitions in Magnetization for Core-Surface Nanoparticles

Abstract

One important issue raised in magnetism studies is the thermal response of various magnetic properties. This topic is known as the magnetic thermal hysteresis MTH which is principally associated with magnetic phase transitions. The MTH is of particular interest for both quantum and applied physics researches on magnetization of nanomaterials. Hysteresis of the temperature-induced structural phase transitions in some materials and nanostructures with first-order phase transitions reduces useful magnetocaloric effect to transform cycling between martensite M and austenite A phases under application. In additional, the size, surface and boundary effects on thermal hysteresis loops have been under consideration for the development of research on nanostructured materials. Experimental data indicate that nanostructured materials offer many interesting prospects for the magnetization data and for understanding of temperature-induced M-A phase transitions. In this chapter, we have presented a review of the the latest theoretical developments in the field of MTH related to the structural phase transitions for the core-surface nanoparticles based on the fundamental formulation of pair approximation in Kikuchi version.

Characterizing Curie and Néel Point Phase Transitions via Thermal Techniques

“…Thermal hysteresis is considered first order as it occurs in only magnetocaloric materials (mostly of first‐order magnetic shape memory alloys), where heating and cooling are involved. [ 62 ] An observed thermal hysteresis in DSC (during heating and cooling) would lead to a first‐order transition when both endothermic and exothermic peaks are visible around the Curie point. [ 28 ] Figure 3a of iron shows this thermal hysteresis (in DSC during heating and cooling).…”