High sensitive spin spectroscopy using terahertz wave

2015 Fiscal Year Final Research Report

• Project/Area Number: 25286063
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Optical engineering, Photon science
• Research Institution: Osaka University (2014-2015); Chiba University (2013)
• Principal Investigator: Nakajima Makoto 大阪大学, レーザーエネルギー学研究センタ, 准教授 (40361662)
• Co-Investigator(Kenkyū-buntansha): OTO KEN-ICHI 千葉大学, 大学院理学研究科, 教授 (30263198)
• Co-Investigator(Renkei-kenkyūsha): SUEMOTO TOHRU 東京大学, 物性研究所, 教授 (50134052)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: テラヘルツ波 / スピントロニクス / スピンダイナミクス / 磁性体 / メタマテリアル / 近接場

Outline of Final Research Achievements

We studied the spin dynamics and control of spin system in weak ferromagnetic materials using the magnetic field component of THz pulses. We developed the high intensity THz pulses with the high peak electric field up to 300 kV/cm. We succeeded in amplifying the amplitude of spin precession by fabricating the metal microstructure (split ring resonator) on sample surface. The enhancement factor is about one order. We succeeded in controlling the macroscopic magnetization direction by using coherent control technique of THz and optical pulse excitation in spin reorientation phase transition. Our results indicate that even the small-amplitude spin precession can induce macroscopic change of spin order by utilizing phase transition process, extending the potential of THz application to controlling magnetic domains within picoseconds time- and subwavelength spatial resolution.

Free Research Field

光物性