Magnetoresistance of a Polycrystalline InSb Disk with anEmbedded Au Core

Suh, Jooyoung; Kim, Wonyoung; Chang, Joonyeon; Han, Song; Kim, Eun Kyu

doi:10.3938/jkps.55.577

Cited by 9 publications

(16 citation statements)

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“…These systems consist of an outer semiconducting disk (radius ) with an embedded metallic inclusion (radius ) modelled in two dimensions. The filling factor of the system can be defined as the ratio of the radius of the metallic droplet to the radius of the entire disk (α = / ) and has a huge effect on the resultant magnetoresistance [1,2,6,10,11]. The largest magnetoresistance effect observed by Solin et al occurred in a system with a filling factor of 13/16 [1].…”

Section: Modelling Proceduresmentioning

confidence: 90%

“…The EMR effect has been shown to be a geometric effect where the expulsion of current from the metallic region is more significant than the ordinary magnetoresistance of the two components. The EMR effect has not only been reproduced in circular system geometries but it has been shown that conformal mapping can produce a linear EMR system equivalent in behaviour to the circular disk geometry [1,[3][4][5][6][7][8][9]. It has been shown that the finite element method (FEM) can be used to create models that give an excellent description of experimental EMR results.…”

Section: Introductionmentioning

confidence: 99%

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Extraordinary magnetoresistance: sensing the future

Hewett

Kusmartsev

2012

Open Physics

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Abstract:Simulations utilising the finite element method (FEM) have been produced in order to investigate aspects of circular extraordinary magnetoresistance (EMR) devices. The effect of three specific features on the resultant magnetoresistance were investigated: the ratio of the metallic to semiconducting conductivities (σ M /σ S ); the semiconductor mobility; and the introduction of an intermediate region at the semiconductormetal interface in order to simulate a contact resistance. In order to obtain a large EMR effect the conductivity ratio (σ M /σ S ) is required to be larger than two orders of magnitude; below this critical value the resultant magnetoresistance effect is dramatically reduced. Large mobility semiconductors exhibit larger EMR values for a given field (below saturation) and reduce the magnetic field required to produce saturation of the magnetoresistance. This is due to a larger Hall angle produced at a given magnetic field and is consistent with the mechanism of the EMR effect. Since practical magnetic field sensors are required to operate at low magnetic fields, high mobility semiconductors are required in the production of more sensitive EMR sensors. The formation of a Schottky barrier at the semiconductor-metal interface has been modelled with the introduction of a contact resistance at the semiconductor-metal interface. Increasing values of contact resistance are found to reduce the EMR effect with it disappearing altogether for large values. This has been shown explicitly by looking at the current flow in the system and is consistent with the mechanism of the EMR effect. The interface resistance was used to fit the simulated model to existing experimental data. The best fit occurred with an interface with resistivity of 1.55×10 −4 Ωm (overestimate). The EMR effect holds great potential with regard to its future application to magnetic field sensors. The design of any such devices should incorporate high mobility materials (such as graphene) along with the specific features presented in this paper in order to produce effective magnetic field sensors. 72.20.My, 72.15.Gd PACS (2008):

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Section: Modelling Proceduresmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Extraordinary magnetoresistance: sensing the future

Hewett

Kusmartsev

2012

Open Physics

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“…This leads to two regimes: one of low resistance at low fields ͑short circuit͒, here the majority of the current flows through the metallic region; the other of high resistance at high fields ͑open circuit͒, here the current is expelled from the metallic region and is forced to flow around the outer semiconducting material of much higher resistance. Since its discovery, EMR has been shown to arise in various experimental systems, 5,6 including linear devices produced via conformal mapping. 7 Using the finite-element method via COMSOL MULTIPHYS-ICS ͑Ref.…”

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confidence: 99%

Geometrically enhanced extraordinary magnetoresistance in semiconductor-metal hybrids

Hewett

Kusmartsev

2010

Phys. Rev. B

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Citation: HEWETT Extraordinary magnetoresistance ͑EMR͒ arises in hybrid systems consisting of semiconducting material with an embedded metallic inclusion. We have investigated such systems with the use of finite-element modeling, with our results showing good agreement to existing experimental data. We show that this effect can be dramatically enhanced by over four orders of magnitude as a result of altering the geometry of the conducting region. The significance of this result lies in its potential application to EMR magnetic field sensors utilizing more familiar semiconducting materials with nonoptimum material parameters, such as silicon. Our model has been extended further with a geometry based on the microstructure of the silver chalcogenides, consisting of a randomly sized and positioned metallic network with interspersed droplets. This model has shown a large and quasilinear magnetoresistance analogous to experimental findings.

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“…These results provide the basis of the initial work presented in this Thesis. Firstly, the discovery of the EMR effect by Solin et al is outlined, followed by discussion of later experimental results that use the same materials in the disk's construction 10,84 . Next, experimental results obtained for systems with the same circular geometry but with different materials are considered.…”

Section: Chapter 3 Circular Geometry Emr Devicesmentioning

confidence: 99%

“…The systems were then patterned into the circular van der Pauw disk geometry using photolithography, with induced coupled plasma reactive ion etching used to create the concentric hole of varying filling factors. The holes were metallised with a Ti/Au stack (gold being the dominant component) and the contact pads finally deposited via DC magnetron sputtering and fabricated via a lift off process 10 . Figure 3.5…”

Section: Experimental Datamentioning

confidence: 99%