Magnetic thermal stability of permalloy microstructures with shape-induced bi-axial anisotropy

Abstract

We study the thermal stability of the magnetization states in permalloy microstructures in the form of two crossing elongated ellipses, a shape which yields effective bi-axial magnetic anisotropy in the overlap area. We prepare the structure with the magnetization along one of the easy axes of magnetization and measure the waiting time for switching when a magnetic field favoring the other easy axis is applied. The waiting time for switching is measured as a function of the applied magnetic field and temperature. We determine the energy barrier for switching and estimate the thermal stability of the structures. The experimental results are compared with numerical simulations. The results indicate exceptional stability which makes such structures appealing for a variety of applications including magnetic random access memory based on the planar Hall effect.

Magnetization switching of multi-state magnetic structures with current-induced torques

“…2(d) shows very sharp switchings between the different remanent states. Please note that a comprehensive study of the magnetic properties of structures such as Device 3 is presented in refs 38 , 39 . Additional magnetic characterization is presented in the supplementary material.…”

Thermodynamics of emergent magnetic charge screening in artificial spin ice

“…For each individual probability distribution, the error is assessed by calculating a confidence interval of 95% (ref. 22 ) ( Supplementary Information ). The obtained probabilities are fitted using a Kohlrausch function 23 , with β being the stretch parameter 2 23 24 ( Supplementary Fig.…”

“…Here, the error is assessed by employing a bootstrapping algorithm with a confidence interval of 95% (ref. 22 ) ( Supplementary Information ). The curve is then fitted by an Arrhenius-type function .…”

“…For the Arrhenius plot, the error is estimated by employing a bootstrapping algorithm with a confidence interval of 95% (ref. 22 ). At each temperature, one thousand calculated data sets are generated randomly from the existing experimental data.…”

Imaging the stochastic microstructure and dynamic development of correlations in perpendicular artificial spin ice

“…However, near the coercive field, thermal fluctuations can be surprisingly significant in understanding the behavior of nanomagnetic systems. [23,24] A non-negligible fraction of islands might be caused to switch in a slightly different field by a thermal fluctuation in a given run, and the "misstep" would then be amplified and propagated by island interactions. One might expect these propagated missteps to lead to a decrease in the zero magnetization overlap as the interactions are increased.…”