The spin pumping effect with different carrier type and resistivity of silicon substrates

Yi-Chien Weng^1,2*, C.-T. Liang¹, J. G. Lin²

¹Graduate Institute of Applied Physic, National Taiwan University, Taipei, Taiwan
²Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan

* Presenter:Yi-Chien Weng, email:yichienweng@gmail.com

Spin pumping effect in silicon is interesting and important for the applications in spintronic devices. In this work, we use the cobalt films on silicon (Si) substrates to study the spin pumping effect and understand the relation between spin pumping efficiency and the carrier of Si. The cobalt thin film was deposited on Si substrates with different carrier type and resistivity. The resistivity are 3000、10、0.1、0.005 ohm-cm for the p-type Si substrates and the resistivity is 10 ohm-cm for n-type Si substrate. The thickness of cobalt thin film are changed from 5 to 40 nm. The quantitative analysis of charge current (I_c)、damping constant (α) and spin mixing conductance (g_↑↓) is obtained by analyzing ISHE and ferromagnetic resonance (FMR) data. With same resistivity, the value of g_↑↓ and I_c for Co/n-type Si is larger than those of Co/p-type Si. The value of I_c is dependent on the resistivity of substrate, and its maximum value of 1 μA is found in the Co film on the Si of 0.1 ohm-cm.

†This work is financially supported by the Ministry of Science and Technology of R.O.C. and National Taiwan University under the projects of MOST105-2112-M-002-010-MY3 and NTU-107L900803.

Keywords: spin pumping, silicon, cobalt