arXiv subjects

Moty Schultz

Publications and source records attributed to Moty Schultz.

10 recordsLinked to original sources

arXiv2025

Two-Axis planar Hall magnetic field sensors with sub nanoTesla resolution

Planar Hall effect (PHE) magnetic sensors are attractive for various applications where the field resolution is required in the range of sub-nano Tesla or in Pico Tesla. Here we present a detailed noise study of the PHE sensors consisting of two or three intersecting ellipses. It can be used to measure two axes of the magnetic field in the sensor plane in particular along the two perpendicular easy axes in the overlapping region for two intersecting ellipses and three easy axes at an angle of 60 degrees for three crossing ellipses. Thus, for each remanent magnetic state in the overlap area, the sensor can measure the vector component of the magnetic field perpendicular to the direction of the remanent magnetization. The two field components are measured with a field resolution less than 200 pT/sqrt(Hz) at 10 Hz and 350 pT/sqrt(Hz) at 1 Hz in the same region, while maintaining a similar size and noise level of a single-axis sensor. Furthermore, we discuss here the possible route for future improvement of the field resolution

cond-mat.str-el↗

arXiv2020

A four-state magnetic tunnel junction switchable with spin-orbit torques

We present a magnetic tunnel junction (MTJ) where its two ferromagnetic layers are in the form of a single ellipse (SE) and two-crossing ellipses (TCE). The MTJ exhibits four distinct resistance states corresponding to the four remanent states of the TCE structure. Flowing current in an underlying Ta layer generates in the adjacent TCE structure spin-orbit torques which induce field-free switching of the four-state MTJ between all its resistance states. The demonstrated four-state MTJ is an important step towards fabricating multi-level MTJs with numerous resistance states which could be important in various spintronics applications, such as multi-level magnetic random access or neuromorphic memory.

physics.app-ph↗

arXiv2020

Stabilization of exponential number of discrete remanent states with localized spin-orbit torques

Using bilayer films of $\beta$-Ta/Ni$_{0.8}$Fe$_{0.2}$, we fabricate structures consisting of two, three and four crossing ellipses which exhibit shape-induced bi-axial, tri-axial and quadro-axial magnetic anisotropy in the crossing area, respectively. Structures consisting of N crossing ellipses can be stabilized in 2N remanent states by applying (and removing) an external magnetic field. However, we show that with field-free spin-orbit torques induced by flowing currents in individual ellipses, the number of remanent states grows to 2$^\text{N}$. Furthermore, when the current flows between the edges of different ellipses the number of remanent states jumps to 2$^\text{2N}$, including states which exhibit a $\pi$-N\'{e}el domain wall in the overlap area. The very large number of accessible remanent magnetic states that are exhibited by the relatively simple magnetic structures paves the way for intriguing spintronics applications including memory devices.

cond-mat.mes-hall↗

arXiv2016

Micromagnetic study of equilibrium states in nano hemispheroidal shells

We present results of micromagnetic simulations of thin ferromagnetic nano hemispheroidal shells with sizes ranging from 1 to 50 nm (inside dimensions). Depending on the geometrical and magnetic parameters of the hemispheroidal shell, there exist four different magnetic phases: easy axis, easy plane, onion and vortex. The profile for the vortex magnetization distribution is analyzed and the limitations and applicability of different vortex ansatzes are discussed. In addition, we investigate the total energy density for each of the magnetic distributions as a function of the hemispheroidal shell dimensions.

cond-mat.mes-hall↗

arXiv2013

Thermally activated recovery of electrical conductivity in LaAlO3/SrTiO3

Patterned structures of LaAlO3/SrTiO3 that exhibit a decrease in their electrical conductivity below 30 K, recover their higher conductivity upon warming in a thermally activated process. Two dominant energy barriers $E_b$ are identified: $E_{b1}=0.224\pm0.003$ eV related to conductivity recovery near 70 K and $E_{b2}=0.44\pm0.015$ eV related to conductivity recovery near 160 K. We discuss possible linkage to structural defects such as dislocations and twin boundaries.

cond-mat.str-el↗

arXiv2012

Interplay between sheet resistance increase and magnetotransport properties in ${\rm LaAlO_3}/{\rm SrTiO_3}$

We find that the sheet resistance ($R_s$) of patterned samples of ${\rm LaAlO_3}/{\rm SrTiO_3}$ with a length scale of several microns may increase significantly at low temperatures in connection with driving electrical currents and applying in-plane magnetic fields. As the samples are warmed up, $R_s$ recovers to its original value with accelerated recovery near ${\rm 70 \ K}$ and ${\rm 160 \ K}$. Concomitantly with the increase in $R_s$, the carrier density and the mobility decrease and magnetotransport properties which may be linked to magnetism are suppressed.

cond-mat.mtrl-sci↗

arXiv2011

Scaling and field-induced crossover of the anomalous Hall effect in SrRuO3

We measure the anomalous Hall effect (AHE) resistivity $ρ_{xy}$ in thin films of the itinerant ferromagnet SrRuO$_{3}$. At low temperatures, the AHE coefficient $R_{s}$ varies with $ρ_{xx}^2$ in agreement with side jumps and Berry phase models. At higher temperatures, $R_{s}$ reaches a peak and then changes sign just below $T_{c}$. We find that for all films studied $R_{s}$ scales with resistivity in the entire ferromagnetic phase. SrRuO$_{3}$ films with very low residual resistivity exhibit field induced sign changes of the AHE at low temperatures, suggesting an $ω_c τ$ related crossover.

cond-mat.str-el↗

arXiv2011

Scaling of the anomalous Hall effect in SrRuO$_{3}$

We measure the anomalous Hall effect (AHE) resistivity $ρ_{xy}$ in thin films of the itinerant ferromagnet SrRuO$_{3}$. At low temperatures, the AHE coefficient $R_{s}$ varies with $ρ_{xx}^2$, and at higher temperatures, $R_{s}$ reaches a peak and then changes sign just below $T_{c}$. We find that for all films studied $R_{s}$ scales with resistivity in the entire ferromagnetic phase. We attribute the observed behavior to the contribution of the extrinsic side jumps mechanism and the intrinsic Karplus-Luttinger (Berry phase) mechanism including the effect of finite scattering rates.

cond-mat.str-el↗

arXiv2007

Relaxation of transport properties in electron doped SrTiO3

We electron-dope single crystal samples of SrTiO_3 by exposing them to Ar^+ irradiation and observe carrier mobility similar in its magnitude and temperature dependence to the carrier mobility in other electron-doped SrTiO3 systems. We find that some transport properties are time-dependent. In particular, the sheet resistance increases with time at a temperature-dependent rate, suggesting an activation barrier on the order of 1 eV. We attribute the relaxation effects to diffusion of oxygen vacancies - a process with energy barrier similar to the observed activation energy.

cond-mat.other↗

arXiv2005

Uniaxial magnetocrystalline anisotropy in ${\rm CaRuO_3}$

${\rm CaRuO_3}$ is a paramagnetic metal and since its low temperature resistivity is described by $\rho=\rho_0+AT^\gamma $ with $\gamma \sim 1.5$, it is also considered a non-Fermi liquid (NFL) metal. We have performed extensive magnetoresistance and Hall effect measurements of untwinned epitaxial films of ${\rm CaRuO_3}$. These measurements reveal that ${\rm CaRuO_3}$ exhibits uniaxial magnetocrystalline anisotropy. In addition, the low-temperature NFL behavior is most effectively suppressed when a magnetic field is applied along the easy axis, suggesting that critical spin fluctuations, possibly due to proximity of a quantum critical phase transition, are related to the NFL behavior.

nlin.PS↗