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arXiv · 1810.02551

Ultrafast demagnetization of Pt magnetic moment in L1${}_0$-FePt probed by hard x-ray free electron laser

Kohei Yamamoto·Yuya Kubota·Motohiro Suzuki·Yasuyuki Hirata·Kou Takubo·Yohei Uemura·Ryo Fukaya·Kenta Tanaka·Wataru Nishimura·Takuo Ohkochi·Tetsuo Katayama·Tadashi Togashi·Kenji Tamasaku·Makina Yabashi·Yoshihito Tanaka·Takeshi Seki·Koki Takanashi·Hiroki Wadati
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Abstract

We demonstrate ultrafast magnetization dynamics in a 5d transition metal using circularly-polarized x-ray free electron laser in the hard x-ray region. A decay time of light-induced demagnetization of L1${}_0$-FePt was determined to be $τ_\textrm{Pt} = 0.6\ \textrm{ps}$ using time-resolved x-ray magnetic circular dichroism at the Pt L${}_3$ edge, whereas magneto-optical Kerr measurements indicated the decay time for total magnetization as $τ_\textrm{total} = 0.1\ \textrm{ps}$. A transient magnetic state with the photo-modulated magnetic coupling between the 3d and 5d elements is firstly demonstrated.

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Kohei Yamamoto, Yuya Kubota, Motohiro Suzuki, Yasuyuki Hirata, Kou Takubo, Yohei Uemura, Ryo Fukaya, Kenta Tanaka, Wataru Nishimura, Takuo Ohkochi, Tetsuo Katayama, Tadashi Togashi, Kenji Tamasaku, Makina Yabashi, Yoshihito Tanaka, Takeshi Seki, Koki Takanashi, Hiroki Wadati. 2018-10-05. Ultrafast demagnetization of Pt magnetic moment in L1${}_0$-FePt probed by hard x-ray free electron laser. https://doi.org/10.1088/1367-2630%2Fab5ac2

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