Extrinsic spin Hall effects measured with lateral spin valve structures

Abstract

The spin Hall effect (SHE), induced by spin-orbit interaction in nonmagnetic materials, is one of the promising phenomena for conversion between charge and spin currents in spintronic devices. The spin Hall (SH) angle is the characteristic parameter of this conversion. We have performed experiments of the conversion from spin into charge currents by the SHE in lateral spin valve structures. We present experimental results on the extrinsic SHEs induced by doping nonmagnetic metals, Cu or Ag, with impurities having a large spin-orbit coupling, Bi or Pb, as well as results on the intrinsic SHE of Au. The SH angle induced by Bi in Cu or Ag is negative and particularly large for Bi in Cu, 10 times larger than the intrinsic SH angle in Au. We also observed a large SH angle for CuPb but the SHE signal disappeared in a few days. Such an aging effect could be related to a fast mobility of Pb in Cu and has not been observed in CuBi alloys.

Room-temperature spin thermoelectrics in metallic films

“…Similarly, for the spin Hall effect its T dependence should allow to establish its specific intrinsic or extrinsic origin [27,28]. The latter is still a somewhat controversial issue, in particular in Au and Pt [11,[28][29][30].…”

Inverse spin Hall effect in a closed loop circuit

“…(3). We note that unlike the case of the lateral spin valve device [7,11,12,14], λ 1D M , which is needed to obtain I S , cannot be directly determined on the same device. Therefore, as shown in Table I, we have referred to λ 1D M reported in our previous works [7,13] to obtain α 1D H ; α 1D H = −0.11 for Cu 99.5 Bi 0.5 and α 1D H = 0.014 for Pt.…”

“…In the present work, we prepared two types of samples, is the saturation field of magnetization of the Py wire, as already shown in our previous reports [7,11,12,14]. What is interesting to note is the amplitude of R ISHE , i.e., ∆R ISHE .…”

“…In Fig. 1(a), we show the principle of ISHE in an SHE ring using the spin absorption method [7,[11][12][13][14]. When the electric current I flows from the Py wire to the left side of the Cu wire, the resulting spin accumulation induces a pure spin current (I S ) on the right side of the Cu wire.…”

Spin relaxation characteristics in Ag nanowire covered with various oxides

“…15 If Bi diffuses into Ag and forms AgBi diluted alloy, a sign of SHA due to extrinsic spin Hall effect should be negative. 16 Therefore, we believe that the Bi diffusion is not a dominant origin of the spin relaxation in the Ag wire. We here discuss the interface scattering contribution imp surf in the probability imp .…”