Simulation optimization of performance for extraordinary magnetoresistance sensor in low-field

Huang, Tiantian; Ye, Lingyun

doi:10.1109/icemi.2013.6743224

Cited by 3 publications

(4 citation statements)

References 17 publications

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“…Optimizing the device geometry was further found to highly increase device performance where shaping the metallic inclusion as a symmetric Hall bar [14,32] or square [33] was shown to enhance the MR response by several orders of magnitude. However, to date, geometric optimization was done only on symmetric structures [2,14,[32][33][34][35][36][37][38][39][40]. These symmetric EMR devices produce large MR values with a symmetric magnetoresistance response where R(B) = R(−B) around zero magnetic field [13,15,19,32,33,41].…”

Section: Introductionmentioning

confidence: 99%

“…These symmetric EMR devices produce large MR values with a symmetric magnetoresistance response where R(B) = R(−B) around zero magnetic field [13,15,19,32,33,41]. The symmetric behavior leads to the sensitivity [dR/dB] B→0 = 0, which is undesirable for detecting weak magnetic fields [40,42]. Asymmetric geometries in EMR devices can therefore provide a way to tune the device, beyond previous studies on inducing asymmetry in the magnetoresistance of EMR devices by changing the contact configuration [2,33,34,36,38,40,[42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

“…The symmetric behavior leads to the sensitivity [dR/dB] B→0 = 0, which is undesirable for detecting weak magnetic fields [40,42]. Asymmetric geometries in EMR devices can therefore provide a way to tune the device, beyond previous studies on inducing asymmetry in the magnetoresistance of EMR devices by changing the contact configuration [2,33,34,36,38,40,[42][43][44][45]. This forms an alternative approach where the asymmetries are directly built into the EMR device itself to form an asymmetric sensor response, independently of the contact location.…”

Section: Introductionmentioning

confidence: 99%

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Symmetry breaking in magnetoresistive devices

et al. 2022

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Detecting weak magnetic fields is paramount in areas such as scanning magnetometers and manipulation of magnetic nanoparticles, thus rendering it crucial to increase the weak-field sensitivity for developing nextgeneration magnetic sensors. The current approaches for high-sensitivity sensors, such as superconducting quantum interference devices, are complex and expensive. By contrast, magnetoresistive sensors and particularly extraordinary magnetoresistive sensors offer a simple operation at room temperature but, to date, at inferior sensitivity. To overcome these challenges, we induce device symmetry breaking to enhance the weak magnetic field sensitivity in semiconductor-metal hybrid structures exhibiting extraordinary magnetoresistance. Retaining the device mirror symmetry yields symmetric magnetoresistance curves with R(B) = R(−B), which results in inferior detection of weak magnetic fields as [dR/dB] B→0 = 0. Using finite element modeling, we study the change in device behavior as the symmetry is broken by varying the device geometry by spatially varying the constituent material properties or both. We show that symmetry breaking has three important implications: First, breaking the mirror symmetry causes an asymmetric sensor response with R(B) = R(−B), benefiting from a largely enhanced sensitivity to weak magnetic fields and detection of the magnetic field direction. Second, an interplay with the Hall effect causes a large negative magnetoresistance exceeding 79% at B = 1 T and room temperature without magnetic constituents or explicit optimization of this property. Third, the asymmetric geometries can be used as a key ingredient toward designing on-demand magnetoresistive characteristics such as linearity at low magnetic fields, step functions, and magnetic switchlike behavior. These implications pave the way for asymmetric topology optimization of magnetoresistive devices with unparalleled performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Symmetry breaking in magnetoresistive devices

et al. 2022

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“…The material requirements sparked an interest in studying the behavior of EMR in various high-mobility materials, including InSb [8,[12][13][14][15][16][17], InAs [18][19][20], GaAs [21][22][23][24] and graphene [25][26][27][28][29][30]. Beyond investigating different material platforms and material parameters, there has also been a strong interest in exploring various EMR geometries [2,[31][32][33][34][35][36][37][38][39][40][41]. Four of the key geometries explored for EMR are displayed in figure 2, which include the concentric circular devices, bar-shaped devices, the asymmetric off-center circular devices and more exotic multi-branched devices.…”

Section: Introductionmentioning

confidence: 99%

Universal material trends in extraordinary magnetoresistive devices

Erlandsen,

Désiré Pomar,

Kornblum

et al. 2023

J. Phys. Mater.

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Extraordinary magnetoresistance (EMR) is a geometric magnetoresistance emerging in hybrid systems typically comprising a high-mobility material and a metal. Due to a field-dependent redistribution of electrical currents in these devices, the electrical resistance at room temperature can increase by 10^7% when applying a magnetic field of 5 T. Although EMR holds considerable potential for realizing sensitive, all-electronic magnetometers, this potential is largely unmet. A key challenge is that the performance of EMR devices depends very sensitively on variations in a vast parameter space where changes in the device geometry and material properties produce widely different EMR performances. The challenge of navigating in the large parameter space is further amplified by the poor understanding of the interplay between the device geometry and material properties. By systematically varying the material parameters in four key EMR geometries using diffusive transport simulations, we here elucidate this interplay with the aim of finding universal guidelines for designing EMR devices. Common to all geometries, we find that the sensitivity scales inversely with the carrier density, while the MR reaches saturation at low carrier densities. Increasing the mobility beyond 20,000 cm^2/Vs is required to observe strong EMR effects at 1 T with the optimal magnetoresistance observed for mobilities between 100,000-500,000 cm^2/Vs. An interface resistance below 10^-4 Ohm*cm^2 between the constituent materials in the hybrid devices was also found to be a prerequisite for very high magnetoresistances in all geometries. By further simulating several high-mobility materials at room and cryogenic temperatures, we conclude that encapsulated graphene and InSb are amongst the most promising candidates for EMR devices showing high magnetoresistance exceeding 10^7% below 1 T at room temperature. This study paves the way for understanding how to realize EMR devices with record-high magnetoresistance and high sensitivity for detecting magnetic fields.

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