Laser-induced magnetization reversal investigated by time-resolved x-ray measurements

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K17722
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics I
• Research Institution: The University of Tokyo
• Principal Investigator: Wadati Hiroki 東京大学, 物性研究所, 准教授 (00579972)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 磁化反転 / レーザー / X線

Outline of Final Research Achievements

We tried to reveal the mechanism of magnetization reversal in ferromagnets by laser. As an experimental technique, we used time-resolved x-ray spectroscopy by synchronicity-radiation x-ray and x-ray free electron laser (XFEL). We mainly measured x-ray magnetic circular dichroism (XMCD). We performed time-resolved XMCD measurements in BL3 in SACLA (XFEL facility in Japan). By shining 800 nm Ti:sapphire laser as a pump light onto alloy FePt thin films with room-temperature ferromagnetism, we succeeded in time-resolved XMCD measurements at Pt L edges. The time scale of demagnetization is about 1 ps, found to be longer than that of Fe sites. Such element-resolved spin dynamics was first revealed by time-resolved XMCD.

Free Research Field

光物性