Experimental demonstration of 55-fs spin canting in photoexcited iron nanoarrays
Abstract
As magnetic storage density approaches 1TB/in2, a grand challenge is looming as how to read/write such a huge amount of data within a reasonable time. The ultrafast optical manipulation of magnetization offers a solution, but little is known about the intrinsic speed limit of quantum spin switching. Here, we report that low-energy 50-fs laser pulses can induce spin canting in Fe nanoparticles within 55 fs, breaking the previous record by at least one order of magnitude. Both linearly and circularly polarized light can be used to tilt spins. In our model, the incident laser field first excites the orbital angular momentum, and through spin-orbit coupling, the spin cants out-of-plane and results in a distinctive diamond hysteresis loop. The spin canting time decreases with spin angular momentum. This spin canting is not limited to Fe nanoparticles and is also observed in Fe/Pt and Fe3O4 nanoparticles. Our results demonstrate the potential of magnetic nanostructures as a viable magnetic medium for high density and fast-switching magnetic storage devices.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 20, 2017
- Source ID
- 10.1063/1.4977097
Entities
People
- G. P. Zhang
- Wei Lai
- Yu Gong
- Yuhang Ren
- Zehra Cevher
Organizations
- Air Force Office of Scientific Research
- City University of New York
- Hunter College
- Indiana State University