Magnetization reversal via internal spin waves in magnetic nanoparticles

Abstract

By numerically solving the equations of motion for atomic spins we show that internal spin-wave processes in large enough magnetic particles, initially in unstable states, lead to complete magnetization reversal and thermalization. The particle's magnetization strongly decreases in the middle of reversal and then recovers. We identify two main scenarios, exponential and linear spin-wave instabilities. For the latter, the longitudinal and transverse relaxation rates have been obtained analytically. Orientation dependence of these rates leads to a nonexponential relaxation of the particle's magnetization at long times.

14 PR pages, 5 figure captions, submitted to PRB. All figures are oversize and do not fit into this archive. Please, get the full version from http://www.lehman.edu/faculty/dgaranin/Intrinsic_relaxation.pdf

References in corpus (5)

• Thermal fluctuations and longitudinal relaxation of single-domain magnetic particles at elevated temperatures
• Phonon superradiance and phonon laser effect in nanomagnets
• Towards Microscopic Understanding of the Phonon Bottleneck
• Phonon bottleneck in the low-excitation limit
• Magnetization reversal and nonexponential relaxation via instabilities of internal spin waves in nanomagnets

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