Exchange coupling torque in ferrimagnetic Co/Gd bilayer maximized near angular momentum compensation temperature. Issue 1 (December 2018)

• Record Type: Journal Article
• Authors: Bläsing, Robin; Ma, Tianping; Yang, See-Hun; Garg, Chirag; Dejene, Fasil; N'Diaye, Alpha; Chen, Gong; Liu, Kai; Parkin, Stuart
• Is Part Of: Nature communications. Volume 9:Issue 1(2018)
• Page Start: 1
• Page End: 8
• Publication Date: 2018-12
• Subjects: Biology -- Periodicals; Physical sciences -- Periodicals; 505
• DOI: 10.1038/s41467-018-07373-w
• Languages: English
• ISSNs: 2041-1723

Abstract

Abstract Highly efficient current-induced motion of chiral domain walls was recently demonstrated in synthetic antiferromagnetic (SAF) structures due to an exchange coupling torque (ECT). The ECT derives from the antiferromagnetic exchange coupling through a ruthenium spacer layer between the two perpendicularly magnetized layers that comprise the SAF. Here we report that the same ECT mechanism applies to ferrimagnetic bi-layers formed from adjacent Co and Gd layers. In particular, we show that the ECT is maximized at the temperatureT A where the Co and Gd angular momenta balance each other, rather than at their magnetization compensation temperatureT M . The current induced velocity of the domain walls is highly sensitive to longitudinal magnetic fields but we show that this not the case nearT A . Our studies provide new insight into the ECT mechanism for ferrimagnetic systems. The high efficiency of the ECT makes it important for advanced domain wall based spintronic devices. High speed current induced domain wall motion is key to various spintronic applications, such as memory-storage. Here the authors show that the motion of chiral domain walls in Co/Gd bilayer structures is controlled by an exchange coupling torque that is maximized at the temperature where the Co and Gd angular momenta exactly balance each other