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Title: Size dependence of magnetization switching and its dispersion of Co/Pt nanodots under the assistance of radio frequency fields

We have studied the dot size dependence of microwave assisted magnetization switching (MAS) on perpendicular magnetic Co/Pt multilayer dot array. The significant microwave assistance effect has been observed over the entire dot size D ranging from 50 nm to 330 nm examined in the present study. The MAS behavior, however, critically depends on D. The excitation frequency dependence of the switching field is well consistent with the spin wave theory, indicating that the magnetization precession in MAS is in accordance with the well defined eigenmodes depending on the dot diameter. The lowest order spin wave is only excited for D ≤ 100 nm, and then the MAS effect is well consistent with that of the single macrospin prediction. On the other hand, higher order spin waves are excited for D > 100 nm, giving rise to the significant enhancement of the MAS effect. The dispersion of MAS effect also depends on D and is significantly reduced for the region of D > 100 nm. This significant reduction of the dispersion is attributed to the essential feature of the MAS effect which is insensitive to the local fluctuation of anisotropy field, such as defect, damaged layer, and so on.
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)
  2. Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578 (Japan)
  3. (Japan)
Publication Date:
OSTI Identifier:
22273666
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; COBALT; EXCITATION; FLUCTUATIONS; FREQUENCY DEPENDENCE; HETEROJUNCTIONS; INTERFACES; LAYERS; MAGNETIZATION; MICROWAVE RADIATION; PLATINUM; QUANTUM DOTS; RADIOWAVE RADIATION; SPIN WAVES