What is it about?
Heat-assisted magnetization reversal in external magnetic fields is the key process in state-of-the-art magnetic recording. Therefore understanding the fundamental limits on the speed of magnetization reversal may have tremendous consequences for future magnetic data storage technologies. Here we aim to reveal these limits by heating a ferrimagnetic iron garnet across the compensation temperature in magnetic fields up to 30 T. Although in thermodynamics such heating in an external magnetic field of 3 T must result in a precessional reversal of the magnetizations, experimentally no dynamics is observed within the first 2 ns. Our results show that if the applied field is below the spin-flop value and the magnetizations of the sublattices are in a collinear state, magnetization reversal cannot be launched by the heating alone. Launching the magnetization reversal requires an initial tilt of the magnetizations and thus can experience substantial delays.
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Why is it important?
Revealing the fundamental limits on the speed of magnetization reversal, our paper significantly advances the fields of magnetization dynamics triggered by femtosecond laser pulses, magnetization reversal, and magnetic recording induced by light.
Perspectives
Here we found that the state with canted spins is more susceptible to laser heating, and the spin reversal in dielectrics can be much faster in the vicinity of the spin-flop transition.
Irina Dolgikh
Radboud Universiteit
Read the Original
This page is a summary of: Spin dynamics driven by ultrafast laser-induced heating of iron garnet in high magnetic fields, Applied Physics Letters, January 2022, American Institute of Physics,
DOI: 10.1063/5.0076442.
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