Study on voltage-induced change of interface magnetic anisotropy at ferromagnetic-oxide interface toward ultralow power consuming non-volatile memories

2015 Fiscal Year Final Research Report

• Project/Area Number: 26630291
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: The University of Tokyo
• Principal Investigator: Koji Kita 東京大学, 工学(系)研究科(研究院), 准教授 (00343145)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 界面磁気異方性 / 強磁性体 / 電界効果 / 不揮発性メモリ / 化学状態

Outline of Final Research Achievements

We investigated the impacts of dielectric material selections on the voltage-induced change of interface anisotropy energy (Kint) at ferromagnetic CoFeB - dielectric interfaces. First we examined the　effects　of　ultrathin　metal　insertion　between　the　ferromagnetic　and　oxides. This does not induce any nonvolatile change of Kint, however, the amount of voltage-induced change of Kint was enlarged.　This　effect　was　pronounced　especially　when　an　element　with　small　electronegativity, as Zr for example, was employed for the metal insertion layer. In addition an enhancement of both Kint and its voltage-induced change was found when oxide at the interface was partially replaced by fluoride. These results clearly show that the chemical states and compositions of the interface dielectrics are crucially important to maximize the voltage-induced effects.

Free Research Field

電子デバイス材料工学