Manipulation of spin current using a lateral spin valve with ferromagnetic/nonmagnetic bilayer spin channels

Takashi Kimura^1*

¹Physics, Kyushu University, Fukuoka, Japan

* Presenter:Takashi Kimura, email:t-kimu@phys.kyushu-u.ac.jp

Generation, manipulation and detection of spin currents are important issues for the developments of spintronic devices because a spin current plays an important role in spin-dependent transport and spin-transfer switching. Lateral spin valve structure provides an ideal platform for investigating the intriguing properties of spin current precisely because of its flexible electrode design. Especially, recent development of the highly spin polarized ferromagnetic electrodes enable us to observe the sufficiently large spin-dependent signal even at room temperature. In this talk, I introduce the efficient way for manipulating the spin current by using a lateral spin valve with a nonmagnetic(NM)/ ferromagnetic(FM) metal bilayer spin channel.
As shown in Figs. 1a and 1b, in the NM/FM bilayer channel, since the spin relaxation time depends on the relative angle between the injected spin and the magnetization, the spin accumulation in the NN can be modulated by the magnetization direction. Figure 1c shows the field dependence of the nonlocal spin valve signal. In addition to the conventional signal changes due to the parallel and anti-parallel transitions, the broad signal change is observed during the entire field sweep. This broad change can be quantitatively understood by the modulation of the spin absorption. Since the modulation ratio increases with increasing the spin polarization of the spin absorber, it is possible to produce the spin-resistance switching devices.
We will also present the results on the Bi/Ag bilayer spin channel for the efficient inducement of the spin Hall effect.

Keywords: Spin injection, Pure spin current, Spin absorption , Spin relaxation