講演情報
[8a-E208-11]Nanosecond Critical Spin Fluctuations in Antiferromagnets Revealed by Asynchronous-Sampling Ultrafast Spin Noise Spectroscopy
〇Kohsuke Ataka1, Kazuki Ikoma1, Takayuki Kurihara2, Shinichi Watanabe1 (1.Keio Univ., 2.The Univ. of Tokyo.)
キーワード：
noise、fluctuation、spin
For next-generation spin-switching devices based on phase transitions, understanding magnetic fluctuations near the transition is essential. Ultrafast spin noise spectroscopy has been developed as a method to investigate such magnetization fluctuations through their temporal autocorrelation function, and has enabled the observation of picosecond critical fluctuations. However, conventional measurements have been limited to delay times of about 100 ps, preventing access to longer-time relaxation dynamics. To overcome this limitation, we developed ultrafast spin noise spectroscopy based on asynchronous optical sampling, which extends the measurable delay-time window by a factor of 80 to 8 ns. This extended time window allowed us to directly observe nanosecond-scale critical relaxation that had not been sufficiently accessible with conventional methods.