Nano-fabricated perpendicular-magnetized electrodes for lateral Spin Valves and observation of the Nernst effect


  Nathan Chejanovsky [1]  ,  Amos Sharoni [1]  
[1] Department of Physics and Institute of Nanotechnology & Advanced Materials, Bar Ilan University

Lateral spin valves (LSVs), composed of two ferromagnetic (FM) electrodes connected by a non-magnetic (NM) channel, are basic building blocks for multi-terminal spintronics device. Their study supplies much interesting physical understanding of spin injection and propagation in a variety of materials including metals, semiconductors and superconductors. The FMs almost always have in plane magnetic shape anisotropy . There are a number of advantages in using FMs with perpendicular magnetic anisotropy (PMA). For one, they show magnetic stability for relatively smaller sizes, making them less sensitive to scaling down of devices. In addition, using PMA FMs will enable measurement configurations of lateral devices that are difficult otherwise. These include the Spin Hall effect, or anisotropic spin scattering in the NM channel. To date there are almost no reports of LSVs with PMA FMs. This is an outcome of the difficulty in fabricating nano-scale electrodes with PMA retaining an efficient spin injection between the FM and NM channel.  We present an efficient fabrication process for Co/Ni and Co/Pd multi-layered FM with PMA which overcomes these obstacles. We show that our LSVs keep their PMA properties and that spin injection is possible after process completion. In addition, an unexpected asymmetric voltage signal is observed in the non-local measurements, which is attributed to the devices magnetic geometry and a Nernst effect.