Attempt to measure magnetic hyperfine fields in metallic thin wires under spin Hall conditions using synchrotron-radiation Mssbauer spectroscopy

Mibu, Ko*; Mitsui, Takaya; Tanaka, Masaaki*; Masuda, Ryo*; Kitao, Shinji*; Kobayashi, Yasuhiro*; Yoda, Yoshitaka*; Seto, Makoto*

Measurement of the magnetic hyperfine fields in metallic thin wires under spin Hall conditions was attempted using the emerging technique synchrotron radiation Mssbauer spectroscopy. A Mssbauer probe layer of Fe(0.2 nm), Fe(0.6 nm), or Sn(0.6 nm) was embedded as an electron spin detector near the surfaces of V, Au, Pt, and Fe wires. The magnitudes of the magnetic hyperfine fields at the Fe and Sn nuclear sites that could be enhanced by nonequilibrium conduction electron spin polarization were measured both without and with the application of an electric current along the wire. Changes in the Mssbauer spectra were not clearly observed, indicating that the magnetic hyperfine field induced by nonequilibrium spin polarization is smaller than the detection limit at least for the measured systems and conditions.