Strategy to reduce minimal magnetization switching field for Stoner particles

Abstract

A strategy is proposed aimed at substantially reducing the minimal magnetization switching field for a Stoner particle. Unlike the normal method of applying a static magnetic field which must be larger than the magnetic anisotropy, a much weaker field, proportional to the damping constant in the weak damping regime, can be used to switch the magnetization from one state to another if the field is along the motion of the magnetization. The concept is to constantly supply energy to the particle from the time-dependent magnetic field to allow the particle to climb over the potential barrier between the initial and the target states.

Energy dissipation and switching delay in stress-induced switching of multiferroic nanomagnets in the presence of thermal fluctuations

“…Thus, switching trajectories initiating from a stagnation point are very slow. 25,26 In order to eliminate the long tails in the switching delay distribution and thus decrease the mean switching delay, one can apply a small static bias magnetic field that will shift the peak of h initial distribution away from the easy axis, so that the most probable starting orientation will no longer be a stagnation point. This field is applied along the out-of-plane hard axis (þx-direction) so that the potential energy due to the applied magnetic field becomes E mag ðtÞ ¼ ÀM V H sinhðtÞ cos/ðtÞ, where H is the magnitude of magnetic field.…”

Shape anisotropy effect on magnetization reversal induced by linear down chirp pulse

“…Under the circularly polarized DCMWP and spin polarized current, the magnetization dynamics m is governed by the Landau-Lifshitz-Gilbert (LLG) equation 7,9,37,44…”

“…Over the past two decades, several controlling parameters/driving forces are discovered to achieve fastest magnetization reversal with low cost. Namely, magnetization reversal using a constant magnetic field 6,7 , reversal by microwave field of constant frequency or time dependent frequency, either with or without a polarized electric current [8][9][10][11][12][13][14][15][16][17][18][19] and by spin transfer torque (STT) or spin orbit torque (SOT) [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] . All methods mentioned above are suffering from specific drawbacks 6,[35][36][37][38][39][40][41] .…”

Subnanosecond magnetization reversal of a magnetic nanoparticle driven by a chirp microwave field pulse

“…However, in case of the STT-MRAM or SOT-MRAM based device fabrication, the requirement of a large current density is an obstacle since it generates Joule heat which limits the device durability and reliability [23,24,25,26,27,28,29]. Later on, people digress to utilize the microwave field of constant or time dependent frequency, either with or without a polarized electric current, to induce magnetization reversal [30,31,32,33,34,35,36,37,38].…”