The universal criterion for switching a magnetic vortex core in soft magnetic nanodots
The universal criterion for ultrafast vortex core switching between core-up and -down vortex bi-states in soft magnetic nanodots was empirically investigated by micromagnetic simulations and combined with an analytical approach. Vortex-core switching occurs whenever the velocity of vortex core motion reaches a critical value, which is {nu}{sub c} = 330 {+-} 37 m/s for Permalloy, as estimated from numerical simulations. This critical velocity was found to be {nu}{sub c} = {eta}{sub c}{gamma} {radical}A{sub ex} with A{sub ex} the exchange stiffness, {gamma} the gyromagnetic ratio, and an estimated proportional constant {eta}{sub c} = 1.66 {+-} 0.18. This criterion does neither depend on driving force parameters nor on the dimension or geometry of the magnetic specimen. The phase diagrams for the vortex core switching criterion and its switching time with respect to both the strength and angular frequency of circular rotating magnetic fields were derived, which offer practical guidance for implementing vortex core switching into future solid state information storage devices.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Materials Sciences Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 941692
- Report Number(s):
- LBNL-1151E; PRLTAO; TRN: US200825%%703
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
Similar Records
Observation of Defect-Assisted Magnetic Vortex Core Reversal at Ultralow Critical Velocity
Microwave absorption properties of permalloy nanodots in the vortex and quasi-uniform magnetization states