材料和材料机理:发现世界上性能最高的磁性制冷材料:氢液化的高效率

材料和材料机理:发现世界上性能最高的磁性制冷材料:氢液化的高效率

-促进氢液化的高效率,这对于实现氢社会至关重要-

NIMS:物质物质机制

通过机器学习,我们发现了用于氢液化的世界上性能最高的磁性制冷材料。

期望这将降低生产液化氢的成本,这是实现氢社会的主要障碍。

https://www.jst.go.jp/pr/announce/20200512/pdf/20200512.pdf

Machine-learning-guided discovery of the gigantic magnetocaloric effect in HoB2 near the hydrogen liquefaction temperature

Pedro Baptista de Castro, Kensei Terashima, […]Yoshihiko Takano

Published: 12 May 2020

NPG Asia Materials volume 12,

Article number: 35 (2020) Cite this article

Abstract

Magnetic refrigeration exploits the magnetocaloric effect,

which is the entropy change upon the application and removal of magnetic fields in materials, providing an alternate path for refrigeration other than conventional gas cycles.

While intensive research

has uncovered a vast number of magnetic materials that exhibit a large magnetocaloric effect, these properties remain unknown for a substantial number of compounds.

To explore new functional materials in this unknown space, machine learning is used as a guide for selecting materials

that could exhibit a large magnetocaloric effect.

By this approach,

  1. HoB2 is singled out and synthesized, and
  2. its magnetocaloric properties are evaluated,

leading to the experimental discovery of a gigantic magnetic entropy change of 40.1 J kg−1 K−1 (0.35 J cm−3 K−1) for a field change of 5 T in the vicinity of a ferromagnetic second-order phase transition with a Curie temperature of 15 K.

This is the highest value reported so far,

to the best of our knowledge, near the hydrogen liquefaction temperature;

thus, HoB2 is a highly suitable material for hydrogen liquefaction and low-temperature magnetic cooling applications.

https://www.nature.com/articles/s41427-020-0214-y