酸化マグネシウムMTJ素子を中心としたスピントロニクス技術の進展

カテゴリ: 論文誌(論文単位)

グループ名: 【C】電子・情報・システム部門

発行日: 2013/03/01

タイトル(英語): Recent Developments of Spintronics Device Technologies Based on Magnetic Tunnel Junctions with Magnesium Oxide Tunnel Barrier

著者名: 湯浅　新治（産業技術総合研究所 ナノスピントロニクス研究センター）

著者名(英語): Shinji Yuasa (National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center)

キーワード: スピントロニクス，磁気抵抗，磁気トンネル接合，酸化マグネシウム，MRAM，スピントルク　　spintronics，magnetoresistance，magnetic tunnel junction，magnesium oxide，MRAM，spin-transfer torque

要約(英語): A magnetic tunnel junction (MTJ) consisting of a thin insulating layer (a tunnel barrier) sandwiched between two ferromagnetic electrodes exhibits the tunnel magnetoresistance (TMR) effect due to spin-dependent electron tunneling. Since the discovery of room-temperature TMR in the mid-1990s, MTJs with an amorphous aluminum oxide (Al-O) tunnel barrier have been studied extensively. Such MTJs exhibit a magnetoresistance (MR) ratio of several tens of percent at room temperature and have been applied to magnetoresistive random access memory (MRAM) and the read heads of hard disk drives. MTJs with MR ratios substantially higher than 100%, however, are desired for next-generation spintronic devices. In 2001, first-principle theories predicted that the MR ratios of epitaxial Fe/MgO/Fe MTJs with a crystalline MgO(001) barrier would be over 1000% due to the coherent tunneling of specific Bloch states. In 2004, MR ratios of about 200% were obtained for MgO-based MTJs. MTJs with a CoFeB/MgO/CoFeB structure were developed for practical application and found to have MR ratios of above 200% and other practical properties. This article reviews the physics of magnetoresistance in MTJs and the application of MTJs to various spintronic devices such as magnetic sensors, spin-transfer-torque MRAM with perpendicular magnetization, and novel microwave devices.

本誌: 電気学会論文誌C（電子・情報・システム部門誌） Vol.133 No.3 （2013） 特集Ⅰ：電磁波の技術と科学および信号処理　特集Ⅱ：電子・情報・システム分野の最先端技術

本誌掲載ページ: 471-478 p

原稿種別: 解説／日本語

電子版へのリンク: https://www.jstage.jst.go.jp/article/ieejeiss/133/3/133_471/_article/-char/ja/