Pi pulses in a ferromagnet: Simulations for yttrium iron garnet

Lim, Jinho; Zhang, Zhaohui; Garg, Anupam; Ketterson, J. B.

doi:10.1016/j.jmmm.2021.167787

Cited by 5 publications

(1 citation statement)

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“…The reasoning is that at small sizes, the exchange interaction favors parallel alignment of the spins and suppresses the dipolar instabilities. In previous work, we have used OOMMF to simulate YIG cylinders with (d, h) = (25,50)nm, (25,100)nm and (75,150)nm, where we have attempted to reverse the magnetic moment of the cylinder by applying pi-pulses 10,11 , as in NMR 12 . We found that by chirping the frequency of the pulse, we could achieve reversal in the 25 nm diameter samples, but not in the larger ones.…”

Section: Introductionmentioning

confidence: 99%

Ferromagnetic Resonance Modes in the Exchange-Dominated Limit in Cylinders of Finite Length

2021

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We analyze the magnetic mode structure of axially-magnetized, finite-length, nanoscopic cylinders in a regime where the exchange interaction dominates, along with simulations of the mode frequencies of the ferrimagnet yttrium iron garnet. For the bulk modes we find that the frequencies can be represented by an expression given by Herring and Kittel by using wavevector components obtained by fitting the mode patterns emerging from these simulations. In addition to the axial, radial, and azimuthal modes that are present in an infinite cylinder, we find localized "cap modes" that are "trapped" at the top and bottom cylinder faces by the inhomogeneous dipole field emerging from the ends. Semi-quantitative explanations are given for some of the modes in terms of a one-dimensional Schrodinger equation which is valid in the exchange dominant case. The assignment of the azimuthal mode number is carefully discussed and the frequency splitting of a few pairs of nearly degenerate modes is determined through the beat pattern emerging from them.

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Section: Introductionmentioning

confidence: 99%