Simulations of magnetic hysteresis loops at high temperatures

M. L. Plumer, J. van Ek, J. P. Whitehead, T. J. Fal, J. I. Mercer
2014 Journal of Applied Physics  
Articles you may be interested in Effects of grain microstructure on magnetic properties in FePtAg-C media for heat assisted magnetic recording Magnetic and structural properties of hexagonal-close-packed-CoCrPt-C granular media for high areal density recording 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
more » ... nt 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. V C 2014 AIP Publishing LLC. [http://dx.
doi:10.1063/1.4896582 fatcat:zbemb3ig6bfhtbxnlm55mnsmym