Crossover in heating regimes of thermally assisted magnetic memories

Abstract

This work investigates the tunnel junction heating process for micrometer and submicrometer size junctions to be used in a thermally assisted magnetic random access memories write scheme. The time evolution of the heating process was obtained from experimental measurements and numerical thermal simulations. Simulation results show an initial temperature regime at very short pulse widths associated with the intrinsic heating of the junction (adiabatic regime). In this regime, for the same power density, the temperature increase is independent of the junction area. In the studied geometry, for pulse widths around 1ns and higher an additional heating occurs in the electrical leads (diffusion regime). The write power density is in this case lower for large junction areas. The use of thermal barriers is an effective mean to decrease the power density required for writing and to eliminate its junction area dependence.

Spintronic Devices for Memory and Logic Applications

“…It is of the order of 10-20 ns. As a result, the write cycle time can be of the order of 30 ns (Sousa et al, 2006). Figure 2.9 illustrates the implementation of the thermal assistance combined with STT (TAS þ STT).…”

Numerical analysis of thermally assisted spin-transfer torque magnetization reversal in synthetic ferrimagnetic free layers

“…Thermal assistance effects have been reported in conventional MRAM, where the magnetization reversal was carried out with Oersted fields. [3][4][5] Recent numerical and theoretical studies suggest the considerable thermal effects on STT switching. [6][7][8][9] However, the feasibility of thermally assisted switching in practical STT-MRAM has not been clarified properly.…”

Spin-wave thermal population as temperature probe in magnetic tunnel junctions

“…These statistical methods are undermined by their questionable description of the switching phenomena and the influence of the temperature thereon. Advanced models like the numerical solving of the heat diffusion equation using finite element codes 11 have usually large uncertainties because they often rely on thermal conductivities that are loosely known at the nanoscale.…”