Spin-Valve Heads for 20 Gbit/inch² Recording

Abstract

Spin-valve (SV) heads with antiferromagnetic control layers for 20 Gbit/inch 2 recording were designed by solving the Landau-Lifshitz-Gilbert equation. The calculated SV-head model has a read track width of 500 nm and a detected minimum bit length of about 50 nm recorded on a medium whose thickness, t mag , is 14 nm, and the product of remanent flux density, B r , and thickness, t mag , is 50 Gµm. The head-to-medium spacing is 30 nm. When the sensing-current density is less than about 5.0 × 10 7 A/cm 2 , the thickness of the pinning layer and the free layer is appropriate to be 2.0 nm and 3.0 nm, respectively. The resolution, V high /V low , is about 0.67 when the optimum shield gap length, G, is 80 nm. The resolution depends on the sensingcurrent density, J , as well as the gap length G. We obtained a low-density output voltage of 700 µV p-p , which is practically applicable, by selecting the optimum element size.

Theoretical investigations of spin splittings in asymmetric AlSb/InAs/GaSb heterostructures and the possibility of electric field induced magnetization

“…Useful spintronic devices can be devised if such control is achieved. A number of such devices have already been proposed [5][6][7][8], yet the search for phenomena which can lead to spin based devices is widespread [9][10][11]. Studies of asymmetric quantum wells have been carried out both theoretically and experimentally in other systems [12][13][14][15].…”