[22a-A205-1~11] 10.2 スピン基盤技術・萌芽的デバイス技術

▲ [22a-A205-1] Detection of thermal magnon current mediated by coherent magnon via spin qubits in diamond

〇Dwi Prananto¹、Yuta Kainuma¹、Kunitaka Hayashi¹、Norikazu Mizuochi²、Ken-ichi Uchida^3,4、Toshu An¹ (1.JAIST、2.Kyoto Univ.、3.NIMS、4.IMR Tohoku Univ.)

キーワード：Diamond NV center, Spin qubit, Thermal magnon

In recent decades, thermal magnon has been the subject of intensive studies due to its potential in computing and thermoelectric conversion technologies^1,2). The advancement in the study of thermal magnon and its applications are benefited from the ubiquitous use of a transport measurement based on the inverse spin Hall effect (ISHE). Here, we present an alternative method to probe thermal magnon current propagating in a magnetic insulator yttrium iron garnet under a temperature gradient using a quantum sensor: electron spins associated with nitrogen-vacancy (NV) defect centers in diamond³⁾. Thermal magnon current is observed as an altering coherent rotation (Rabi oscillation) frequency of the NV spins in a beam-shaped bulk diamond that is resonantly coupled with a coherent magnon. Additionally, alteration in NV spin relaxation rates depending on the applied temperature gradient is observed under a non-resonant NV spins excitation condition using a nanodiamond. The detection of thermal magnon current by this method may lead to a better insight into the study and practical applications of spin caloritronics through a high spatial resolution study enabled by the NV spin’s atomic size and its single-spin detection resolution²⁾.
Acknowledgments: N.M. acknowledges support from KAKENHI (Grant No. 15H05868) and MEXT Q-LEAP (Grant No. JPMXS0118067395), Japan.
References: 1) G. E. W. Bauer, et al., Nat. Mater. 11, 391 (2012). 2) J. Wrachtrup, et al., J. Magn. Reson. 269, 225 (2016). 3) D. Prananto, Y. Kainuma, K. Hayashi, N. Mizuochi, K. Uchida and T. An, Phys. Rev. Appl. 16, 064058 (2021).