Effect of sputtering power on the magnetic properties in Pt/Co system for spin-orbit torque devices

Abstract

As CMOS integration continues to advance, the semiconductor industry faces several challenges. Spintronics has emerged as a promising technology to go “beyond CMOS” and overcome these limitations.[1] Spintronics is a field of research that ut ilizes not just electron charge but also electron spin, introducing a new degree of freedom. The key materials employed in spintronics predominantly consist of magnetic materials. Although there are wide variety of categories in magnetic materials, perpendicular magnetic anisotropy (PMA) which prefer magnetization alignment perpendicular to the film plane gets significant notice because of its advantage in terms of information density.[2] To control these magnetic elements, techniques like spin-transfer torque (STT) and spin-orbit torque (SOT) are utilized. Notably, the SOT method offers the advantage of high speed and is gaining attention in various devices.[3]To improve better SOT devices, researchers aim to manipulate the material properties of magnetic materials using a range of methods.[4] In particular, there are several research exploring how variations in sputtering power can influence material properties.[5][6] Given this, we hypothesized that altering the sputtering power would likewise lead to changes in the physical properties of the magnetic material. In this report, we investigate the impact of the deposition power of the Co layer on the material properties in the Pt/Co bilayer structure, which is a representative system exhibiting PMA characteristics and controllable through SOT. The structure was deposited using a magnetron DC sputtering method on an oxidized silicon substrate with a thickness of 300 nm. Sputtering power was varied from 40W to 80W at 10W intervals. We confirmed how this variation in deposition power affects magnetic anisotropy. We believe that this research holds significant potential for advancing the development of spintronic SOT based devices that rely on PMA.