Ordinary magnetoresistance omr fornonmagneticmetals, mreffects at low fields are very small, although the effect can become quite large for high fields. Mr contributions which can enhance mr in silicon up to. This work focuses on measuring superlattice samples of composition bi2te3sb2te3 that are removed from. A potential difference is applied to a wire that is placed close to the magnetic material on disk or tape. An example of magnetoresistance due to direct action of magnetic field on electric current can be studied on a corbino disc see figure. By coupling hall effect and nonlinear transport property in silicon, all four basic boolean logic operations including and, nand, or and nor, can be programmed at room temperature with high output ratio in one siliconbased device. Geometrical magnetoresistance and negative differential. Linear magnetoresistance in ntype silicon due to doping. Linear magnetoresistance in n type silicon due to doping. For instance, siliconbased devices exhibit a weak emr effect because of the low. Enhanced low field magnetoresistance in germanium and silicon. Negative and anisotropic magnetoresistance in phosphorus. Magnetoresistance technique for determining crossplane.
Geometrical enhancement of lowfield magnetoresistance in silicon. The phenomenon of diodeassisted mr is firstly discovered in silicon and offers. Semiconductor nonlinear effect assisted magnetoresistance. It arises from the deformation of current paths, which causes a part of the hall field to be. Currentperpendiculartoplane magnetoresistance in chemical. Semiconductor nonlinear effect assisted magnetoresistance and. Extremely large magnetoresistance in borondoped silicon. The extraordinary mr geometry produces the highest low field mr while the corbino geometry produces the largest high field magnetoresistance. Geometrical enhancement of low field magnetoresistance in silicon. For instance, silicon based devices exhibit a weak emr effect because of their low carrier.
Geometrical enhancement of low field magnetoresistance in. We demonstrate that any material with an unsaturating linear intrinsic mr, will also have an unsaturating linear corbino mr, and that the ideal material for linear mr sensors in conventional geometries. More recent discoveries are the giant magnetoresistance gmr 2,3, the colossal magnetoresistance cmr 4,5, the tunnel magnetoresistance tmr 6, the extraordinary magnetoresistance emr7,andthelargemagnetoresistance lmr 8. Very large tunneling magnetoresistance in layered magnetic.
All these spectacular properties were found in either magnetic systems or in special geometrical structures. Sep 14, 2011 geometrical enhancement of lowfield magnetoresistance in silicon. Giant magnetoresistance gmr is a quantum mechanical magnetoresistance effect observed in multilayers composed of alternating ferromagnetic and nonmagnetic conductive layers. The 3contact device provides a considerable boost of the low field response. Here, we investigate linear magnetoresistance in ptfeptznofept multilayer magnetic sensor, where fept and fe ferromagnetic layers exhibit outofplane and inplane magnetic anisotropy, respectively. Because this is an intrinsically spatial effect, the geometry of the device can be used to enhance imr further. Most of the cppmr devices are artificial layered structures of ferromagnets and nonmagnets, and in these devices, mr manifests, due to spindependent carrier transmission through the constituent layers. Without a magnetic field, the battery drives a radial current between the rims.
Room temperature magnetooptic effect in silicon lightemitting diodes. On the other hand, the geometrical magnetoresistance due to the lorentz force gives rise to the quadratic field dependence of mr at low magnetic field 48. Magnetoresistance is proportional to the strength of the magnetic field, with a larger field producing a higher resistance. The magnetoresistance is related to the magnetic field strength as b2 in the standard configuration, but the field dependence is also influenced by device geometry. Magneto resistor characteristics magneto resistors make use of the magnetoresistance effect. Currentperpendiculartoplane cpp magnetoresistance mr effects are often exploited in various state of theart magnetic field sensing and data storage technologies. Enhanced roomtemperature geometric magnetoresistance in. Here the applied magnetic field is perpendicular to the graphenesi configuration plan, and the temperature is 80 k. It arises from the deformation of current paths, which causes a part of the hall field to be detected at the voltage probes. Tan, geometrical enhancement of lowfield magnetoresistance in silicon, nature. At the same time, an asymmetric magnetoresistance, which. Pdf the extraordinary magnetoresistance emr effect is a change in the.
Thus the resistance of the material decreases in a magnetic field. Geometrical enhancement of lowfield magnetoresistance in silicon article in nature 4777364. Sep 14, 2011 geometrical enhancement of low field magnetoresistance in silicon wan, caihua. Magnetoresistance mr measurements is used to extract the electron mobility on strained and unstrained thin film fully depleted silicononinsulator metaloxidesemiconductor fieldeffect. For instance, siliconbased devices exhibit a weak emr effect because of their low carrier. Enhancement of organic magnetoresistance by electrical conditioning, applied physics letters 92 2008, 193309. Magnetoresistance can originate from the magnetic field dependence of physical properties, or can be geometric in origin.
This effect was first discovered in 1856 by william thomson, also known as lord kelvin. Electrical resistivity and hall effect part i overview. Enhanced roomtemperature geometric magnetoresistance in inhomogeneous narrowgap semiconductors s. The enhanced lowfield magnetoresistance property is ascribed to the introduced insulating phase at the grain boundaries. Giant magnetoresistance in magnetic metallic multilayers.
This property is used in computers to read magnetic data. The enhanced low field magnetoresistance property is ascribed to the introduced insulating phase at the grain boundaries. There are a variety of effects that can be called magnetoresistance. Magnetoresistance technique for determining crossplane mobility in superlattice devices. We report the observation of a large linear magnetoresistance in the ohmic regime in commonplace commercial ntype silicon wafer with a p dopant density of 1. We expect that this gemr could be also realized in other semiconductors. Nio films, which can be attributed to the antiferromagnetic properties of the co 3 o 4 phase. Electrically tunable large magnetoresistance in graphene. Magnetic states of cri 3 and tunneling magnetoresistance. They allow one to dx xxp take into account, during the interpolation, the dependences of geometrical magnetoresistance and negative differential mobility in semiconductor devices v. Mobility investigation by geometrical magnetoresistance in. Here, we report on a large positive magnetoresistance mr over 80% at a magnetic field of 2.
This is just within the low doping regime where the mr is large. Geometrical enhancement of lowfield magnetoresistance in silicon wan, caihua. Extremely large magnetoresistance in borondoped silicon j. Recently, a strongly geometrydependent magnetoresistance effect, the. We report a large but asymmetric magnetoresistance in silicon pn junctions, which contrasts with the fact of magnetoresistance being symmetric in magnetic metals and semiconductors. Linear magnetoresistance in ntype silicon due to doping density. Magnetic logic based on diodeassisted magnetoresistance. Dec 30, 2012 with the discovery of giant magnetoresistance gmr, research effort has been made to exploiting the influence of spins on the mobility of electrons in ferromagnetic materials andor artificial structures, which has lead to the idea of spintronics.
Lowvoltage magnetoresistance in silicon request pdf. With the discovery of giant magnetoresistance gmr, research effort has been made to exploiting the influence of spins on the mobility of electrons in ferromagnetic materials andor artificial structures, which has lead to the idea of spintronics. Magnetoresistance mr reported in some nonmagnetic semiconductors. Koopmans department of applied physics, cnm, eindhoven university of technology, the netherlands received 21 august 2007. Extraordinary magnetoresistance in semiconductormetal. Spintronic devices operating with pure spin currents represent a new paradigm in nanoelectronics, with a higher energy efficiency and lower dissipation as compared to charge currents. Enhanced low field magnetoresistance in germanium and. Magnetoresistance mr refers to the change in electrical resistance of a material in a magnetic field. It is found that the magnetization of the nanomgo added compounds is highly sensitive to a low applied field below 7 koe compared with.
The geometric mr increases quadrati cally with mobility and magnetic field at low field 5. For heavy phosphorus implantations, the negative magnetoresistance is observed at 77 k and the angular dependences of the magnetoresistance are similar to those of nchannel mosfet. Giant magnetoresistance did not get its name by being a small effect. Giant magnetoresistance in silicon diodeassisted geometrical. The changes produced by the geometries are quite subtle. An additional contribution to the resistance from spin disorder comes from the exchange interaction between the conduction electrons and the local magnetic moments and at low temperatures from the magnonelectron scattering 3. The extraordinary magnetoresistance emr effect is a change in the resistance of a device upon the application of a magnetic field in hybrid structures, consisting of a semiconductor and a metal. This anomalous anisotropy of the magnetoresistance is found to be due to the spatial nonuniform distribution of. The effect is noticed in ferromagnetic materials and dependent on the magnetic field strength and angle between the direction of electric current and the magnetic field.
Magnetoresistance mr measurements is used to extract the electron mobility on strained and unstrained thin film fully depleted silicon oninsulator metaloxidesemiconductor field effect. Thirdly, the asymmetry geometry could enhance the lowmagneticfield. The materials and mechanisms for these four types ofmagnetoresistance are distinctly different. Giant magnetoresistance effect in organic material and its. Colossal positive magnetoresistance in surfacepassivated.
A brief introduction is given to gmr effects from scientific background to experimental observations and theoretical models. The extraordinary mr geometry produces the highest lowfield mr while the corbino geometry produces the largest highfield magnetoresistance. Independent geometrical control of spin and charge. The model for giant magnetoresistance predicts decreasing gmr with disorder enhancement of gmr in cocu multilayers for hot electrons. Geometrical magnetoresistance does not require magnetic materials, and occurs by the effect of the lorentz force on the currentpotential distribution and boundary conditions, similar to the classical hall effect. Enhancement of lowfield magnetoresistance in selfassembled. Jan 25, 2017 here, we propose a novel category of magnetic logic based on diodeassisted magnetoresistance.
Herein, we proposed an empirical model to describe the magnetotransport characteristics, particularly the positive nonsaturating magnetoresistance observed in the surfaceengineered sto. We are going to treat the magnetoresistance of metals in a quite general and simple manner. Currentperpendiculartoplane cpp magnetoresistance mr effects are often exploited in various stateoftheart magnetic field sensing and data storage technologies. We designed an imr device in which, the inhomogeneity is provided by the pn boundary formed between regions where conduction is. Morpurgo1,2 1department of quantum matter physics, university of geneva, 24 quai ernest ansermet, ch. Giant magnetoresistance effect in organic material and its potential for magnetic sensor mitra djamal1. The mr size is typically represented by the percentage change of the resistance. Pdf extraordinary magnetoresistance in semiconductormetal. With temperature decreasing from 293 k to 100 k, the magnetoresistance sharply increases from 50% to 150% under a magnetic field of 2 t. Pdf linear magnetoresistance in ntype silicon due to. Electrically tunable mr effect of the graphenesi junctions. Fecr multilayers displayed much larger magnetoresistance values than could be accounted for by the magnetoresistance of the individual fe layers themselves. Magnetoresistance mr reported in some nonmagnetic semiconductors particularly. The underlying principle of this phenomenon is a change of the current path in the hybrid structure upon application of a magnetic field, due to the lorentz force.
This cited by count includes citations to the following articles in scholar. By coupling hall effect and nonlinear transport property in silicon, all four basic boolean logic operations including and, nand, or and nor, can be programmed at room temperature with high output ratio in one silicon based device. The 2007 nobel prize in physics was awarded to albert fert and peter grunberg for the discovery of gmr. Geometrical enhancement of lowfield magnetoresistance in silicon the discovery of inhomogeneityinduced magnetoresistance imr in some nonmagnetic semiconductors, in particular silicon, is of great interest to the scientific community. Magnetoresistance is the tendency of a material often ferromagnetic to change the value of its electrical resistance in an externallyapplied magnetic field. All metals have an intrinsic ordinary magnetoresistance omr due to the curving of the conduction electron trajectory in a magnetic field by the lorentz force. The true roomtemperature magnetoresistance of the devices described in ref. Here, we propose a novel category of magnetic logic based on diodeassisted magnetoresistance. This technology, however, will be viable only if the amount of spin current diffusing in a nanochannel can be tuned on demand while guaranteeing electrical compatibility with other device elements, to which it. It consists of a conducting annulus with perfectly conducting rims. High field linear magnetoresistance is an important feature for magnetic sensors applied in magnetic levitating train and high field positioning measurements. Geometrical enhancement of lowfield magnetoresistance in silicon geometrical enhancement of lowfield magnetoresistance in silicon wan, caihua. A twodimensional finite element model is built to simulate the. Geometrical enhancement of low field magnetoresistance in silicon the discovery of inhomogeneityinduced magnetoresistance imr in some nonmagnetic semiconductors, in particular silicon, is of great interest to the scientific community.
Geometrical enhancement of lowfield magnetoresistance in. Extraordinary magnetoresistance effect in semiconductormetal. This enhanced magnetoresistance is attributed to geometry of germanium and nonlinear electrotransport characteristic of silicondiode. Identifying the nature of the magnetic states responsible for the tunneling magnetoresistance, and checking. The combination of high sensitivity to low magnetic fields and large highfield. We designed an imr device in which, the inhomogeneity is provided by the pn boundary formed between regions where conduction is dominated by the. Gmr materials show benefit compare to other low magnetic sensor technology such as high sensitivity, low cost, low power and small size see fig. Anomalous anisotropic magnetoresistance in topological. Co 3 o 4 composite films via polymerassisted deposition meng zhou, yuling li, il jeon, qinghua yi, xuebin zhu, xianwu tang, haiyan wang, ling fei, yuping sun, shuguang deng, yutaka matsuo, hongmei luo, guifu zou. We address the inherent highfield magnetoresistance mr of indium antimonide epilayers on gaas 001, studying the modification of the mr when processed into a set of geometries. Low field magnetoresistance in a 2d topological insulator. Koopmans department of applied physics, center for.