Enhancement of magnetism and magneto-electric coupling in multiferroic structures with geometrical frustration caused by high tetragonality phases

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560007
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied materials science/Crystal engineering
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: RICINSCHI Dan 東京工業大学, 総合理工学研究科(研究院), 准教授 (60403127)
• Co-Investigator(Kenkyū-buntansha): 奥山 雅則 大阪大学, 基礎工学部, 名誉教授 (60029569)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: マルチフェロイック / 第1原理計算 / BiFeO3 / 強誘電性 / 強磁性

Outline of Final Research Achievements

The research project has investigated crystalline materials in which two important properties coexist: ferroelectricity (centers of positive and negative atomic charges are always separated, creating permanent electric dipoles or polarization that can be controlled by external electric field) and ferromagnetism (electrons of certain atoms in the crystal arrange themselves so that their magnetic dipole of spin are uncompensated and aligned). We have studied crystals in the family of BiFeO3. Our atomistic calculations have shown that we can control the atomic displacements (that yield a large/small polarization) by changing the way we fill up the electronic shells of Fe (thus creating a large/small magnetization). Our research revealed that for obtaining large magnetism and ferroelectricity, coupled to each other at room temperature, some exotic crystal symmetries or BiFeO3 (that are normally difficult to stabilize) should be promoted by careful selection of the fabrication conditions.

Free Research Field

物理学