"Entropics": Science and engineering of caloric phenomena related to itinerant-electron magnetism and spin fluctuations

International Workshop on Itinerant-Electron Magnetism

Fujita, Asaya^1 ; Takenaka, Koshi^2

Inorganic Functional Materials Research Institute, Department of Materials and Chemistry, National Institute of Advanced Industrial Science and Technology (AIST Chubu), Nagoya

465-8560, Japan^1

Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya

464-8603, Japan^2

关键词: Anomalous Hall resistivity;    Disordered local moments;    Itinerant-electron magnetisms;    Itinerant-electron metamagnetic transitions;    Magnetocaloric compound;    Paramagnetic phase transitions;    Science and engineering;    Temperature dependence;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/868/1/012004/pdf
DOI  :  10.1088/1742-6596/868/1/012004

来源: IOP

【 摘 要 】

In this paper, the relationship between giant caloric phenomena and itinerant-electron magnetism is examined in order to construct of a newly proposed concept "Entropics", which is a fusion of science and technology with the objective of solving and controlling entropic phenomena. An anomalous hall resistivity is present in the paramagnetic state of the La(Fe0.88Si0.12)13magnetocaloric compound. Further, its coefficient exhibits a Curie-Weiss type temperature dependence, indicating the existence of disordered local moment, even though the Rhodes-Wohlfarth (RW) ratio reveals that the magnetic feature in the system is an itinerant-electron type. In addition, the correlation between the magnitude of the transition entropy change of the itinerant-electron metamagnetic transition and the RW ratio was observed. In the Mn3GaN barocaloric compound, the transition entropy of the first-order antiferromagnetic-paramagnetic phase transition marginally depends on the external pressure, in contrast to the data for Gd5Ge2Si2. The origin of this tendency is phase stability against the pressure, as opposed to large volume change at the transition temperature, which results in an enhancement of the barocaloric effect. The influence of topological frustration is also distinguished by comparing it with that of other Mn-based antiperovskite compounds.