Dresden 2006 – scientific programme

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MA: Magnetismus

MA 31: Magnetic Measuring Techniques

MA 31.2: Talk

Thursday, March 30, 2006, 16:30–16:45, HSZ 103

Extracting the intrinsic switching field distribution in perpendicular media: a comparative analysis — •Michael Winklhofer^1,2 and Gergely Zimanyi¹ — ¹Physics Departement, UC Davis, CA, USA — ²Geophysics Section, LMU, Munich

The quality of recording media depends crucially on the intrinsic (microscopic) switching-field distribution (SFD) of the media particles, which determines both magnetic stability and attainable recording density. We introduce a new method based on the first-order-reversal-curve (FORC) diagram to extract the SFD of perpendicular recording media (PRM). To demonstrate the viability of the method, we micromagnetically simulated FORCs (recoil loops) for PRM with known SFD and compare the extracted SFD with the SFD obtained by means of two different methods that are based on recoil loops, too, which however rely on mean-field approximations and assumptions on the shape of the SFD. The FORC method turns out to be the most accurate algorithm over the technologically relevant range of magnetic quality factors (Q=2 K/(µ₀ M_s²)), where the other methods overestimate the width of the SFD [1]. Moreover, the FORC method directly renders the shape of the SFD, without having to make a priori assumptions on its shape, and allows one to test if and to what degree the underlying assumption model of square hysterons is met.

[1] Winklhofer M., Zimanyi G.T., cond-mat/0509074