Optimisation of applied field pulses for microwave assisted magnetic recording

Abstract

Grains in a recording medium experience field pulses from a write head during recording. In general, a short head field rise time and a square pulse shape have been viewed as optimal. This work investigates the optimum field pulse shape for microwave assisted magnetic recording on single layer and ECC media. A square pulse was found to give the best recording performance on single layer media, but an initially negative field pulse increasing at a constant rate was more suitable for ECC media.

RF assisted switching in magnetic Josephson junctions

“…In this paper, we study the effects of microwave fields on MJJ critical current levels in attempt to find an alternative addressing approach which would minimize the memory cell dimensions. The RF-assisted magnetization switching is a rather well known phenomenon for a wide range of systems such as magnetic clusters, single-domain magnetic particles and magnetic tunnel junctions [19][20][21][22][23][24][25][26][27] , but it has never been investigated on MJJs, although spin wave resonances have been observed in conventional ferromagnetic Josephson junctions 28 . Here we show how this effect of remagnetization boost by RF fields can be used to improve discernibility of two logical states of a superconducting memory element based on Pd 0.99 Fe 0.01 magnetic barrier.…”