skip to main content

SciTech ConnectSciTech Connect

Title: Simulations of magnetic hysteresis loops at high temperatures

The kinetic Monte-Carlo algorithm as well as standard micromagnetics are used to simulate MH loops of high anisotropy magnetic recording media at both short and long time scales over a wide range of temperatures relevant to heat-assisted magnetic recording. Microscopic parameters, common to both methods, were determined by fitting to experimental data on single-layer FePt-based media that uses the Magneto-Optic Kerr effect with a slow sweep rate of 700 Oe/s. Saturation moment, uniaxial anisotropy, and exchange constants are given an intrinsic temperature dependence based on published atomistic simulations of FePt grains with an effective Curie temperature of 680 K. Our results show good agreement between micromagnetics and kinetic Monte Carlo results over a wide range of sweep rates. Loops at the slow experimental sweep rates are found to become more square-shaped, with an increasing slope, as temperature increases from 300 K. These effects also occur at higher sweep rates, typical of recording speeds, but are much less pronounced. These results demonstrate the need for accurate determination of intrinsic thermal properties of future recording media as input to micromagnetic models as well as the sensitivity of the switching behavior of thin magnetic films to applied field sweep rates at higher temperatures.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X7 (Canada)
  2. Western Digital Corporation, San Jose, California 94588 (United States)
  3. Department of Computer Science, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X7 (Canada)
Publication Date:
OSTI Identifier:
22305711
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALGORITHMS; ANISOTROPY; CURIE POINT; FILMS; HEAT; HYSTERESIS; IRON ALLOYS; KERR EFFECT; MAGNETO-OPTICAL EFFECTS; MONTE CARLO METHOD; PLATINUM ALLOYS; SATURATION; SENSITIVITY; SIMULATION; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K