Ultrafast all-optical manipulation of the antiferromagnetic order

2016 Fiscal Year Annual Research Report

• Project/Area Number: 16F16326
• Research Institution: The University of Tokyo
• Principal Investigator: 湯本 潤司 東京大学, 大学院理学系研究科(理学部), 教授 (60443769)
• Co-Investigator(Kenkyū-buntansha): BOSSINI DAVIDE 東京大学, 大学院理学系研究科(理学部), 外国人特別研究員
• Project Period (FY): 2016-10-07 – 2019-03-31
• Keywords: 固体物理 / 超高速スピンダイナミクス / 磁気光学効果 / ME効果 / マルチフェロイクス / 相転移

Outline of Annual Research Achievements

In the past year I managed to fulfill the goals concerning the construction of the experimental set-up. A pump-probe set-up, able to detect the ultrafast optical and magnetic dynamics even in condition of low temperature and high magnetic field has been built. As planned, I employ the fundamental wavelength and the second harmonic of our laser system. Because of technical difficulties regarding the heating of the sample, I changed the material under investigation: I performed measurements of the ultrafast optical and magnetic response of CuB2O4.
Although the sample is different, the goal of the project is still to control the macroscopic magnetic and optical properties of solids on the ultrafast timescale by using laser pulses. An extensive experimental investigation has been begun.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

Realizing the technical difficulties forbidding the realization of the original project, we were forced to change the sample to investigate. Nevertheless, I was able to build a fully operational experimental apparatus, able to detect ultrafast optical and magnetic dynamics in the presence of an intense magnetic field and at los temperature. We identified a material (CuB2O4) that can be properly studied by employing our set-up and we have already started a comprehensive experimental investigation, as originally planned. Also CuB2O4 is a material with magneto-electric coupling and with a long-range magnetic order. Therefore the focus remains on the study of the optical ultrafast manipulation of electronic and magnetic properties of solid-state compounds.

Strategy for Future Research Activity

I aim at completing the experimental investigation of CuB2O4 in the 2017 academic year. In particular, measurements as a function of the laser intensity and polarization will be performed. The effect on the dynamics of the externally applied magnetic field will be investigated as well. Moreover, data analysis and interpretation of the results will be dealt with. In case the results are positive and a satisfactory interpretation is provided, a manuscript will be prepared and published in an international journal. The results will be also presented in domestic and international conferences.