Increases in effective head field gradients in exchange spring media

Lee, Jehyun; Suess, Dieter; Schrefl, Thomas; Dean, Julian; Fidler, Josef
October 2009
Applied Physics Letters;10/26/2009, Vol. 95 Issue 17, p172509
Academic Journal
Finite head field gradients in combination with switching field distribution of individual grains lead to transition jitter in granular recording media. We studied the effective head field gradients in various recording media structures using finite element micromagnetics. Inhomogeneous reversal was strongly induced in exchange spring structures that had a hard layer at the bottom. Due to the inhomogeneous reversal mode the effective head field gradient increases. As a result the transition jitter that is caused by an anisotropy distribution was reduced by more than 50% in exchange spring media compared to single phase media.


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