21 research outputs found
Computational search for ultrasmall and fast skyrmions in the Inverse Heusler family
Skyrmions are magnetic excitations that are potentially ultrasmall and
topologically protected, making them interesting for high-density
all-electronic ultrafast storage applications. While recent experiments have
confirmed the existence of various types of skyrmions, their typical sizes are
much larger than traditional domain walls, except at very low temperature. In
this work, we explore the optimal material parameters for hosting ultra-small,
fast, and room temperature stable skyrmions. As concrete examples, we explore
potential candidates from the inverse Heusler family. Using first-principles
calculations of structural and magnetic properties, we identify several
promising ferrimagnetic inverse Heusler half-metal/near half-metals and analyze
their phase space for size and metastability.Comment: 7 pages, 3 figures, 1 tabl
Reduced sensitivity to process, voltage and temperature variations in activated perpendicular magnetic tunnel junctions based stochastic devices
True random number generators (TRNGs) are fundamental building blocks for
many applications, such as cryptography, Monte Carlo simulations, neuromorphic
computing, and probabilistic computing. While perpendicular magnetic tunnel
junctions (pMTJs) based on low-barrier magnets (LBMs) are natural sources of
TRNGs, they tend to suffer from device-to-device variability, low speed, and
temperature sensitivity. Instead, medium-barrier magnets (MBMs) operated with
nanosecond pulses - denoted, stochastic magnetic actuated random transducer
(SMART) devices - are potentially superior candidates for such applications. We
present a systematic analysis of spin-torque-driven switching of MBM-based
pMTJs (Eb ~ 20 - 40 kBT) as a function of pulse duration (1 ps to 1 ms), by
numerically solving their macrospin dynamics using a 1-D Fokker-Planck
equation. We investigate the impact of voltage, temperature, and process
variations (MTJ dimensions and material parameters) on the switching
probability of the device. Our findings indicate SMART devices activated by
short-duration pulses (< 1 ns) are much less sensitive to
process-voltage-temperature (PVT) variations while consuming lower energy (~
fJ) than the same devices operated with longer pulses. Our results show a path
toward building fast, energy-efficient, and robust TRNG hardware units for
solving optimization problems.Comment: 7 pages, 5 figure