Magnetic refrigerant materials for AMRR for hydrogen liquefaction (JST-Mirai) -Giant magnetocaloric materials with small hysteresis-.
SEPEHRI-AMIN Hossein, TANG Xin, LAI Jiawei, 齋藤 明子, 大久保 忠勝, 宝野 和博 （NIMS）
Abstract:Hydrogen will play a major role in the establishment of carbon neutrality. One of the major challenges is H2 liquefaction required for its storage and transportation. Cryogenic magnetic refrigeration (CMR) is a prospective environmentally friendly and efficient technology for liquefaction of H2. However, the lack of magnetic refrigerant materials with a giant and reversible magnetocaloric effect in a wide temperature range of 77-20 K required for the hydrogen liquefaction is a bottle-neck for practical applications of CMR. Giant magnetocalorimetric effects have been realized in magnetocaloric materials with the first-order magnetic phase transition (FOMT). However, due to the existence of thermal hysteresis in these materials, the magnetocaloric effect is not reversible and they exhibit poor cyclic performance. In this talk, we will demonstrate how the thermal hysteresis can be minimized by modification of alloy composition and microstructure focusing on the Er(Ho)Co2- and La(Fe,Si)13-based systems. We will demonstrate how these fundamental studies have led us to develop series of Er(Ho)Co2-based compounds with giant and reversible magnetocaloric effect covering the range 20 K to 80 K for multi-layer AMRR for hydrogen liquefaction.