清华大学材料科学与工程研究院《材料科学论坛》学术报告
报告时间：2026年10月23日下午14:00-15:00
报告人：Prof. Pham Nam Hai, Institute of Science Tokyo
报告地点：清华大学逸夫技术科学楼B213陶瓷报告厅
邀请人：易迪老师
报告题目：Inverse spin Hall magnetic sensor using topological insulator for 4 Tbit/inch2 HDD
报告摘要：
In recent years, the dazzling growth of online data has put a heavy pressure on hard disk drive (HDD) technology. The areal density of magnetic recording media is expected to exceed 4 Tb/in2 in the upcoming years. To achieve such an ultrahigh areal density, the magnetic read head should be scaled down to less than 20 nm while maintaining a high signal-to-noise ratio (SNR). Such requirements are challenging for the current tunneling magnetoresistance (TMR) reader technology. Recently, we have proposed a spin–orbit torque (SOT) magnetic sensor based on the inverse spin Hall effect that may overcome those challenges. The structure of a SOT reader consists of two layers in minimum: a ferromagnetic (FM) layer and a SOT layer. When applying a charge current between the top shield and the bottom shield, a perpendicular spin polarized current is injected from the FM layer to the SOT layer. The spin polarization direction depends on the magnetization of the FM layer, which senses the media stray magnetic field. The SOT layer converts the spin-polarized current to a charge current and outputs a transverse voltage signal for read-out. We have demonstrated the integration of a BiSb topological insulator layer into SOT readers for large output and high SNR for 4 Tbit/inch2 magnetic recording technology.
报告人简介：
Pham Nam Hai is Professor of Electrical and Electronic Engineering at the Institute of Science Tokyo (formerly Tokyo Institute of Technology), specializing in spintronics. His work spans ferromagnetic nanoclusters and semiconductors, ferromagnet/semiconductor hybrids, and topological insulators and semimetals, with applications to spintronics and AI. He serves as a representative member of the Japan Society of Applied Physics and has held editorial roles at the Magnetics Society of Japan (MSJ), including Editor-in-Chief (Spintronics). He has served on program committees for major meetings such as the Conference on Magnetism and Magnetic Materials (MMM). As a research director for Japan Science and Technology Agency projects, he has collaborated with R&D groups at Kioxia, TDK, Samsung, and Western Digital. Honors include the SSDM Young Researcher Award (2009), Ando Memorial Award (2014), Marubun Research Award (2017), German Innovation Award—Gottfried Wagener Prize (2019), Asian Scientist 100 (2020), and MSJ Outstanding Research Award (2020).