変形金属ベースの磁気冷媒は,室温の用途に適しています
O Tegus1, E Brück, K H J Buschow
1Van der Waals-Zeeman Institut, Universiteit van Amsterdam, The Netherlands.
Nature
|January 24, 2002
まとめ
研究者らは,効率的な室温磁気冷却のための新しい材料,MnFeP0.45As0.55を発見しました. この材料は大きな磁熱効果 (MCE) を表しており,従来の冷却方法の有望な代替案となっています.
科学分野:
- 材料科学 材料科学とは
- 熱力学は熱力学である.
- 凝縮物質物理学 凝縮物質物理学
背景:
- 磁気冷却は,従来の蒸気サイクル冷却の持続可能な代替手段として磁気カロリー効果 (MCE) を利用しています.
- MCEは,磁場を適用/除去すると磁気材料を加熱/冷却し,熱伝導を可能にします.
- 既存のMCE材料には,室温以下で動作するなど,多くの場合制限があります.
研究 の 目的:
- 室温で大きなMCEを示す新しい材料を発見し,特徴づけること.
- この新しい材料が実用的な磁気冷却アプリケーションに持つ可能性を評価する.
- 観測されたMCEに起因する基礎的な物理的メカニズムを理解する.
主な方法:
- MnFeP0.45As0.55化合物の合成と特徴付けについて.
- 異なる磁場 (2Tおよび5T) の下での磁気エントロピーの変化の測定.
- 材料のキュリー温度と冷媒容量の決定.
主要な成果:
- 300 K (室温) 周辺のキュリー温度を持つ材料であるMnFeP0.45As0.55の発見.
- 14.5 J K−1 kg−1 (2 T) と18 J K−1 kg−1 (5 T) の大きな磁気エントロピーの変化を達成しました.
- Gdと比較して優れた冷媒容量と,Gd5Ge2Si2のような巨大MCE材料の同等のエントロピーの変化が示されていますが,それは室温で示されています.
結論:
- MnFeP0.45As0.55は,その大きなMCEのため,室温磁気冷却のための有望な材料です.
- 観測された大きなMCEは,フィールドが誘発した第1次相移行に起因する.
- この発見は,実行可能で,効率的で,潜在的に環境に優しい冷却技術を提供します.
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