[19a-Z19-1~12] 10.4 半導体スピントロニクス・超伝導・強相関

▲ [19a-Z19-1] Ultrafast enhancement of magnetization in ferromagnetic semiconductor (In,Fe)As quantum wells

〇Anh Duc Le^1,2、Masaki Kobayashi¹、Takahito Takeda¹、Kohsei Araki¹、Ryo Okano¹、Toshihide Sumi¹、Masafumi Horio¹、Kohei Yamamoto³、Yuya Kubota⁴、Shigeki Owada^4,5、Makina Yabashi^4,5、Iwao Matsuda¹、Masaaki Tanaka¹ (1.Univ. of Tokyo、2.PRESTO, JST、3.IMS、4.RIKEN、5.JASRI)

キーワード：ferromagnetic semiconductor quantum well, ultrafast magnetization, (In,Fe)As

We demonstrate for the first time sub-ps enhancement of ferromagnetism in two-dimensional (2D) FMS (In,Fe)As/InAs bilayer quantum wells (QWs, Curie temperature T_C ~ 20 K). We conducted pump-and-probe X-ray magneto-optical Kerr effect (XMOKE) measurements at SACLA, using a fs-pulse laser (wavelength 793 nm, pulse width 30 fs) as the pump source and an X-ray free electron laser (XFEL) beam with energy of 52 eV, which is resonant with the M absorption edge of Fe, as the probe. The Kerr rotation angle of the reflected XFEL beam rapidly enhances upon irradiating the QW by the pumping laser pulse. This indicates an extremely fast sub-ps enhancement, corresponding to 667 fs, of the magnetization of the (In,Fe)As/InAs QW.
This work was partly supported by Grants-in-Aid for Scientific Research (19K21961), CREST (JPMJCR1777) and PRESTO (JPMJPR19LB) of JST, and the Spin-RNJ.