Understanding voltage-controlled magnetic anisotropy effect at Co/oxide interface

• Published in: Scientific reports Vol. 13; no. 1; p. 10640
• Main Authors: Nozaki, Tomohiro, Okabayashi, Jun, Tamaru, Shingo, Konoto, Makoto, Nozaki, Takayuki, Yuasa, Shinji
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30.06.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166/987; 639/301/1005/1007; 639/925/357/997; Anisotropy; Annealing; Bias; Circular dichroism; Diffusion; Humanities and Social Sciences; Interfaces; Magnetic Phenomena; multidisciplinary; Oxidation; Oxides; Physical Phenomena; Power consumption; Random access memory; Science; Science (multidisciplinary); Voltage
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-37422-4

The voltage-controlled magnetic anisotropy (VCMA) effect is a key to realising high-speed, ultralow-power consumption spintronic devices. The fcc-Co-(111)-based stack is a promising candidate for the achievement of large VCMA coefficients. However, only a few studies on the fcc-Co-(111)-based stack have been reported and the VCMA effect has not been well understood. Previously, we observed a significant increase in the voltage-controlled coercivity (VCC) in the Pt/Ru/Co/CoO/TiO x structure upon post-annealing. However, the mechanism underlying this enhancement remains unclear. This study performs multiprobe analyses on this structure before and after post-annealing and discusses the origin of the VCMA effect at the Co/oxide interface. X-ray magnetic circular dichroism measurement revealed an increase in the orbital magnetic moment owing to post-annealing, accompanied by a significant increase in VCC. We speculate that the diffusion of Pt atoms into the vicinity of Co/oxide interface enhances the interfacial orbital magnetic moment and the VCMA at the interface. These results provide a guideline for designing structures to obtain a large VCMA effect in fcc-Co-(111)-based stacks.