Cryocooler with Magnetic Regenerator Materials Review Article. The Magnetic Field Influences on the Regenerator Materials and the Proposal of the New Antiferromagnetic Material Ho2Al.

(TAKAHASHI) SAITO Akiko, SAHASHI Masashi, TOKAI Yoichi, HASHIMOTO Takasu

doi:10.2221/jcsj.31.182

Bibliographic Information

Other Title

磁性蓄冷材を使用した小型冷凍機　磁性蓄冷材へ磁場が及ぼす影響の考察および反強磁性蓄冷材Ｈｏ２Ａｌの提案

Description

Many rare-earth compounds have been studied to attain a large volumetric specific heat in cryogenic temperatures and to aim at developing regenerator materials for a regenerative refrigerator. The magnetic specific heats of these materials are so large that the performance of refrigeration for a Gifford-McMahon refrigerator has been greatly improved and helium temperatures have been attained. In an application for the superconducting magnet, the refrigerator must be operated under the magnetic field. So, magnetic regenerator materials are required to be free from the influences of the magnetic field. In this paper, the magnetic field influences on the regenerator materials Er₃Ni, ErNi and Er₃Co, are discussed and Ho₂Al is proposed as a new regenerator material which is free from the influence of the magnetic field. The magnetic properties of Er₃Ni, ErNi and Er₃Co were investigated at cryogenic temperatures in a magnetic field of up to 5 Tesla. The magnetic forces were evaluated for these materials under the magnetic field using the magnetic moment values deduced from the magnetization measurements. The magnetic forces for ferromagnetic materials such as the ErNi and Er₃Co turned out to be one order of magnitude larger than that for antiferromagnetic material Er₃Ni. It was confirmed that the antiferromagnetic material is superior to the ferromagnetic one in case of the exposure to the large magnetic field and large gradient of the field. Further, new antiferromagnetic regenerator materials were searched and Ho₂Al was found to have a volumetric specific heat as large as Er₃Co in the temperature range from 10 to 16K.

Journal

TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)

TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan) 31 (4), 182-189, 1996

CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN

Keywords

Details 詳細情報について

CRID: 1390001204614874880

NII Article ID: 130003673070

DOI: 10.2221/jcsj.31.182

ISSN: 18800408; 03892441

Text Lang: ja

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