[18a-D704-1~11] 10.2 Fundamental and exploratory device technologies for spin

▼ [18a-D704-3] Electrical detection of antiferromagnetic dynamics in GdCo thin films by using a 154 GHz gyrotron irradiation

〇Shinsaku Funada¹, Yuya Ishikawa², Motoi Kimata³, Yuusuke Yamaguchi², Kanata Hayashi², Tomonori Sano², Koki Sugi¹, Yutaka Fuji², Seitaro Mitsudo², Yoichi Shiota^1,4, Teruo Ono^1,4, Takahiro Moriyama^1,4,5 (1.ICR, Kyoto Univ., 2.FIR, Univ. of Fukui, 3.IMR, Tohoku Univ., 4.CSRN, Kyoto Univ., 5.PRESTO, JST)

Keywords:magnetization dynamics, antiferromagnet, ferrimagnet

THz magnetization dynamics is a key property of antiferromagnets that could harness the THz forefront and spintronics.However, the measurement principles used in previous studies rely on the volume of the materials and thus the same principle can hardly be applied for characterizing thin films.
One of the solutions could be the DC voltage detection of the magnetic resonance resulting from a nonlinear coupling of the induction current and the magnetoresistance change. The only concern for this method is that it generally requires a sizable irradiation power of > mWatt, which is to be resolved by the gyrotron irradiation that is introduced in this study.
Test samples, ferrimagnetic Gd_1-xCo_x (20 nm)/ Ta (3 nm), were shaped into a 1.5 mm x 5 mm piece with electric leads connected on the longitudinal ends for measuring DC voltage. DC voltage measurements were carried out with sweeping external magnetic field on irradiating 154 GHz electromagnetic wave. We observed a clear DC voltage peak at a certain magnetic field and the peak shifts with varying the temperature, which are consistent with the resonant properties of GdCo.