[26p-E201-1~12] 10.2 Fundamental and exploratory device technologies for spin

▼ [26p-E201-12] Thermo-spin effects through antiferromagnetic insulator NiO detected by lock-in thermoreflectance

〇(P)Takumi Yamazaki^1,2, Takeshi Seki^1,2, Takahide Kubota^1,2, Koki Takanashi^1,2,3 (1.IMR, Tohoku Univ., 2.CSRN, Tohoku Univ., 3.CSIS, Tohoku Univ.)

Keywords:spin caloritronics, thermoreflectance, antiferromagnetic insulator

We report measurements of the spin-current-induced thermo-spin effects on Pt/antiferromagnetic insulator NiO/CoFeB trilayers. In a normal metal (NM)/ferromagnetic metal (FM) junction, two types of thermo-spin effects occur as a result of the spin Hall effect in NM: magnon-driven and conduction-electron-driven effects. When a charge current is applied to an NM/FM, a temperature change due to the thermo-spin effects is contaminated with the magneto-thermoelectric effect in FM. To eliminate the contamination, we exploited the NM/NiO/FM trilayer, where NiO transports a spin current while providing the electrical insulation between NM and FM. By means of the optical thermometry called a thermoreflectance method, we measured the temperature change due to the thermo-spin effects in Pt/NiO/CoFeB. The NiO thickness dependence of the temperature change gives the spin transmission length of NiO to be λ=19±6 nm, which is of the same order as the reported values. We demonstrate the thermoreflectance-based optical measurement is useful not only for investigating the thermo-spin effects but for clarifying the spin transport in an antiferromagnetic insulator.