Showing papers on "Magnetoresistance published in 1983"
TL;DR: In this article, the conductivity as a function of donor density and uniaxial stress in bulk samples of phosphorus-doped silicon was measured and the transition from metal to insulator is continuous, but sharper than predicted by scaling theories of localization.
Abstract: Millikelvin measurements of the conductivity as a function of donor density and uniaxial stress in bulk samples of phosphorus-doped silicon establish that the transition from metal to insulator is continuous, but sharper than predicted by scaling theories of localization The divergence of the dielectric susceptibility as the transition is approached from below also points out problems in current scaling theories The temperature dependence of the conductivity and the magnetoresistance in the metal indicate the importance of Coulomb interactions in describing the behavior of disordered systems
238 citations
TL;DR: In this paper, the Langer-Neal graph is translated into a transparent physical picture, which represents an interference experiment with conduction electrons split into pairs of waves interfering in the backscattering direction.
Abstract: The resistance of two-dimensional electron systems such as thin disordered films shows deviations from Boltzmann theory, which are caused by quantum corrections and are called "weak localization." Theoretically, weak localization is originated by the Langer-Neal graph in the Kubo formalism. In the present paper this graph is translated into a transparent physical picture. It represents an interference experiment with conduction electrons split into pairs of waves interfering in the backscattering direction. The intensity of the interference (integrated over the time) can be easily measured by the resistance of the film. A simple derivation for this quantum correction to the resistance is given. A magnetic field introduces a magnetic phase shift in the electronic wave function and suppresses the interference after a "flight" time proportional to $\frac{1}{H}$. Therefore, the application of a magnetic field allows observation of the fate of the electron as a function of time. Spin-orbit coupling rotates the spin of the electrons and yields an observable destructive interference, thereby demonstrating the change of sign of the electron-spin function by rotation. Magnetic impurities destroy the coherence of the phase. Therefore, with magnetoresistance measurements one can determine the inelastic lifetime, the spin-orbit coupling time, and the magnetic scattering time of the conduction electrons.
222 citations
TL;DR: The Hall effect and the magnetoresistance of the magnetic field have been measured at temperatures from 0.08 to 10 K and in magnetic fields to 22 T as discussed by the authors, and the low-temperature data suggest a series of transitions induced by an orbital effect from the magnetic fields which progressively reduce the carrier density.
Abstract: The Hall effect and the magnetoresistance of ${(\mathrm{TMTSF})}_{2}$Cl${\mathrm{O}}_{4}$ have been measured at temperatures from 0.08 to 10 K and in magnetic fields to 22 T. The low-temperature data suggest a series of transitions induced by an orbital effect from the magnetic field which progressively reduce the carrier density. Oscillations, apparently Shubnikov-de Haas, also are observed above 10 T and at temperatures up to 10 K.
129 citations
01 Jan 1983
66 citations
Book•
01 Jan 1983
TL;DR: In this article, the quantized hall effect in two-dimensional (2D) systems has been studied in the context of quantization of hall resistivities in 2D electronic systems.
Abstract: Precision determination of h/e2 and the fine-structure constant from magneto-transport measurements on 2D electronic systems.- Gauge invariance and the quantised hall effect in two-dimensional systems.- Some remarks on the present understanding of the quantized hall effect in two dimensions.- Quantum transverse and hall resistivities in silicon MOS inversion layers at temperatures down to 12 mK.- Possible application of the quantized hall resistance to the realization of the electrical units.- Temperature dependence of the quantum hall effect in In0.53Ga0.47As-InP heterojunctions.- The quantized hall resistance and the Josephson effect.- On the two-dimensional wigner localization in high magnetic fields.- Negative magnetoresistance and Anderson localization in Si-MOSFETs and other 2D systems in semiconductor interfaces.- Electron-electron interaction effects in p-type germanium inversion layers.- Anharmonic effects in two-dimensional electron solids in magnetic fields.- Localisation and scaling of resistance of disordered systems including magnetic field effects.- High field magnetotransport IN GaAs/AlGaAs heterojunctions and SI mosfets.- Magnetotransport in GaInAs-InP heterojunctions and superlattices.- Quantum transport in GaInAs-AlInAs heterojunctions.- Bias voltage dependence of the temperature of hot n-Si inversion layer electrons in high magnetic fields.- Magnetoresistance in a two-dimensional impurity band.- Magnetoconductivity and cyclotron resonance studies on Na+-contaminated Si-SiO2-interfaces.- On the screening of impurities by a two dimensional electron gas in high magnetic fields.- Valley phase transition of Si inversion layers in high magnetic fields.- Electrical properties of layered materials in high magnetic fields.- Quantum oscillatory effect in graphite intercalation compounds.- Magneto-optical experiments on a thin InAs LAyer confined between GaSb in a parallel and perpendicular magnetic field.- Electronic structure of semiconductor superlattices.- Inelastic light scattering by two dimensional electron systems in high magnetic fields.- Anomalous cyclotron resonance of 2D electrons in AlxGa1?xAs/GaAs heterojunctions.- Faraday rotation and ellipticity in electron inversion layers of Si MOS structures.- Magnetooptical studies of deep impurities in III-V compounds.- Magneto optics of II-VI compounds under low and high excitation.- Magneto-reflectance of the B-exciton of CdS.- Magneto-optical studies of donor impurities under high pressure.- Magnetically tunable far infrared emitters and detectors.- Magnetooptical studies of phase transition in IV-VI compounds.- Transport properties in the active layer of a double heterostructure infection laser measured by a strong magnetic field.- Quantum oscillations of indirect interband magnetoabsorption below the Burstein edge.- Neutral bound excitons in a magnetic field.- Magneto-oscillation of relaxation time in electron hole-drops.- Experimental verification of nodal surface number conservation rule in magneto-optical effects of hydrogenic exciton.- Identification of contaminating donors in III-V compounds by far-infrared laser magneto-optical studies.- Magnetoplasma oscillations in a small conducting sphere.- Two-Photon spectroscopy in InSb at high magnetic fields.- Electron spin resonance in InSb under uniaxial stress.- Far-Infrared cyclotron resonance of hot carriers in InSb.- Magneto-thermal conductivity oscillations in n-type InSb.- Infrared emission due to the magnetoelectric-photo effect in InSb.- Optically pumped recombination radiation in zincblende semiconductors under crossed magnetic and strain fields.- The metal- non metal transition in n-type InSb in high magnetic fields.- Shubnikov-de Haas effect in heavily doped n-InSb under pressure.- Interaction between T and L minima associated impurity states in n-InSb.- Anomalous NMR relaxation peak in InSb in the extreme quanium limit.- Dielectric function of Zero-Gap HiCdTe and HgMnte in a magnetic field.- Fermi surface properties of Pb71Sn29Te above and below the structural phase transition.- Evidence of fermi level pinning in Pb Sn1-xTex/In at high magnetic fields.- Magnetotransport properties of Hg0.8Cd0.2Te in pulsed fields up to 35 T.- Influence of an acceptor state on transport in zero-gap Hgl?xMnxTe.- Shubnikov-de Haas effect in amorphous Cd3As2.- Hopping conduction in the magnetic field.- Effect of dilute ionized impurities on the magnetoresistivity of Bismuth in high magnetic fields.- A magnetic field induced two-dimensional stripping of the polaron.- Variable range hopping in indium phosphide near the metal non metal transition in presence of a magnetic field.- A kinetic approximation for quantum magneto-transport.- Scattering mechanisms in n-CdTe under classical and quantum limit conditions.- Magnetophonon and magnetoimpurity resonances in N-Germanium.- Classical transport effects revisited : A basis for new applications of high magnetic fields.- Impurities in semimagnetic semiconductors.- Bound magnetic polarons in semimagnetic semiconductors.- "Spin-doping" in semiconductor physics.- Magnetically stimulated conductivity of magnetic semiconductor and related phenomena.- Binding of an electron in the field of a finite electric dipole in a magnetic field.- Low-temperature magnetocapacitance measurements on n-type silicon: Spin-dependent electrical polarizabilities of donor clusters.- Phase transitions in high magnetic fields.- High magnetic field research at the Francis bitter national magnet laboratory.- High magnetic fields at the Clarendon Laboratory, Oxford.- Semiconductor experiments in megagauss and submegagauss fields.- High field superconductors.- The generation of high magnetic fields in Grenoble - installations and magnets.- Magnets I have known.
60 citations
TL;DR: In a quantizing magnetic field, the resistance value of a two-dimensional electron gas between any well-resolved magnetic levels in any open geometry is given by multiple fractions of $\frac{h}{{e}^{2}}$.
Abstract: In a quantizing magnetic field, the resistance value of a two-dimensional electron gas between any well-resolved magnetic levels in any open geometry is given by multiple fractions of $\frac{h}{{e}^{2}}$. Measurements in various geometrical configurations of Si(100) (metal-oxide-semiconductor) transistor yield a well-defined and accurate plateau of these values.
52 citations
TL;DR: In this article, the temperature and magnetic field dependence of the resistivity of thin Mg and Au films are measured and the parameters of weak localization such as the inelastic lifetime and spin-orbit coupling time are evaluated.
Abstract: The temperature and magnetic field dependence of the resistivity of thin Mg and Au films are measured The parameters of weak localization such as the inelastic lifetime ${\ensuremath{\tau}}_{i}(T)$ and the spin-orbit (so) coupling time ${\ensuremath{\tau}}_{\mathrm{so}}$ are evaluated The Mg film which has a small spin-orbit coupling can be changed into a strong spin-orbit coupler by covering it with 025 monolayers of Au Since the inelastic lifetime is not affected by the small amount of Au only one parameter is changed This does not only alter the magnetoresistance but also the temperature dependence of the film resistance The whole set of magnetoresistance curves is well described by the theory The change of the spin-orbit coupling essentially allows one to separate the temperature-dependent resistance caused by weak localization from other temperature-dependent contributions It is consistent with the theory
51 citations
IBM1
TL;DR: In this paper, the superconducting transition temperature T/sub c/ and the magnetoresistance were measured on two-dimensional amorphous W-Re films of various compositions.
Abstract: In this communication we report our findings on two-dimensional amorphous W-Re films of various compositions in which we have studied superconducting fluctuations, the superconducting transition temperature T/sub c/, and the magnetoresistance. We have also measured the dependence of T/sub c/ on sheet resistance. The T/sub c/ data fit well with the predictions of Maekawa and Fukuyama which are based on localization and Coulomb-interaction effects. Inelastic-scattering times derived from these measurements agree with data from phase-slip phenomena.
50 citations
TL;DR: The electrical resistance of a linear chain metal Nb3Te4 was measured from 1.3 to 320 K and the residual resistance ratio R(300 K ) R(4.2 K ) is about 3.8.
44 citations
TL;DR: In this article, the influence of intersubband scattering in GaAs/AlGaAs heterostructures by means of a parallel magnetic field was demonstrated by using a back-side gate voltage which varies the Fermi energy.
37 citations
TL;DR: In this article, spin-flip Raman scattering and magnetization measurements are reported for the semimagnetic semiconductor Cd1-xMnxS, x = 0.023.
TL;DR: In this article, the Shubnikov-de Haas effect in magnetoresistance was investigated in Bi and Bi 100- x Sb x alloys with various x ranging from 0.1 to 12.2 (atomic percent) under pulsed high magnetic fields up to 45 T.
Abstract: Shubnikov-de Haas effect in magnetoresistance was investigated in Bi and Bi 100- x Sb x alloys with various x ranging from 0.1 to 12.2 (atomic percent) under pulsed high magnetic fields up to 45 T. For H //binary, sharp kinks corresponding to the magnetic-field-induced semimetal to semiconductor (SM-SC) transition were observed for x =4.4 in addition to the Shubnikov-de Haas peaks of holes. In pure Bi, SM-SC transition was observed for H //binary at 88 T in the magneto-transmission of the far-infrared radiation. For x >8, on the other hand, semiconductor to semimetal (SC-SM) transition was observed for H //trigonal. In Bi and Bi 95.6 Sb 4.4 for H //binary, band parameters were determined based on the Vecchi et al .'s model, by analysing the Shubnikov-de Haas oscillation and SM-SC transition field.
TL;DR: In this article, the behavior of carbon resistor and capacitive thermometers was investigated from 4.2 to below 0.1 K and to 19 T. The reader is provided with an expression for the magnetoresistance which may be used, with proper precalibration for a particular sensor, to determine the temperature from a reading of the resistance and the magnetic field.
Abstract: We have investigated the behavior of carbon resistor and capacitive thermometers from 4.2 to below 0.1 K and to 19 T. We observe, in agreement with previous work at higher temperatures, a nonmonotonic magnetoresistance in a standard carbon resistor for thermometry below 1.0 K. We provide the reader with an expression for the magnetoresistance which may be used, with proper precalibration for a particular sensor, to determine the temperature from a reading of the resistance and the magnetic field. In addition, we discuss epoxy mixing chambers for dilution refrigerators and discuss results which indicate that certain materials can be magnetized and demagnetized at low temperatures. Finally, we report measurements on two types of capacitive temperature sensors which also exhibit magnetoeffects.
TL;DR: In this article, the angular variations of the magnetisation vector at a series of points across the strip have been calculated and the total energy of the model may be predicted for any combination of conductor angle, anisotropy skew and applied fields.
Abstract: Magnetoresistive sensors are made by photo-etching narrow linear folded tracks in vacuum-deposited permalloy film with uniaxial anisotropy. A large demagnetising field appears across each narrow strip in the resistive pattern: this and the presence of exchange energy, bias fields and the effects of anisotropy, combine to make the choice of optimum anisotropy and current flow directions complex. In the work described here the angular variations of the magnetisation vector at a series of points across the strip have been calculated. The inclusion of an exchange energy term allows the total energy to be determined and the behaviour of the model may be predicted for any combination of conductor angle, anisotropy skew and applied fields. Comparisons made with experimental values show close similarity of form but some quantitative discrepency. A simpler model, in which the permalloy film is assumed to be magnetised as a single domain and the magnetisation vector is constant across the strip is also evaluated.
TL;DR: In this article, the two-dimensional Anderson localization in the weakly localized regime has been investigated and it has been concluded that the anomalous behavior of TiTe 2 is not due to the Kondo effect, but the Anderson localization.
Abstract: Resistivity measurements of TiTe 2 have been made. Above 10 K, a typical metallic behavior has been observed, while at low temperatures an increase of resistivity with a log T dependence has been found. From measurements of magnetoresistance, this anomaly has been concluded to be due to not the Kondo effect but the two-dimensional Anderson localization in the weakly localized regime. Negative magnetoresistance observed for J ⊥ H // c -axis is proportional to H 2 in low fields and to log H in intermediate fields and saturates about 40 kOe. This field dependence is in good agreement with Hikami et al .'s theory based on the two-dimensional localization. Moreover, TiTe 2 seems to be a new system, where two carriers (three-dimensional and two-dimensional) exist and the two-dimensional carriers are considered to be localized at low temperatures.
TL;DR: In this article, the magnetoresistance of amorphous metallic alloys has been measured at temperatures between 16 mK and 4.2K and it was found that the positive positive Delta R(H)/R(0) is independent of the magnetic field direction, proportional to H 1/2 and 104 times greater than the expected normal magnetoreduction.
Abstract: The magnetoresistance Delta R(H)/R(0), of Cu50Ti50 and Cu65Ti35 amorphous metallic alloys has been measured at temperatures between 16 mK and 4.2K. In both samples it was found that the positive Delta R(H)/R(0) is independent of the magnetic field direction, proportional to H1/2 and 104 times greater than the expected normal magnetoresistance. These results are compared with calculations of the magnetoresistance involving the effects of Coulombic interactions.
TL;DR: The magnetoresistance in thin films of silver and gold has been measured in the temperature range 1.1 K −4.2 K as discussed by the authors, which is in good agreement with the theoretical results in weakly localized regime with suitable values of the spin-orbit scattering time.
Abstract: The magnetoresistance in thin films of silver and gold has been measured in the temperature range 1.1 K–4.2 K. It is in good agreement with the theoretical results in weakly localized regime with suitable values of the spin-orbit scattering time. The inelastic scattering time is nearly in inverse proportion to temperature.
TL;DR: In this article, magnetization and magnetoresistance measurements on Ni+21 at % Mn sample were performed and the results were consistent with a low-temperature state, which is quasi-ferromagnetic, with spin-glass and ferromagnetic components.
TL;DR: In this paper, the electrical resistance and magnetic susceptibility of the magnetic superconductor, Y g Co 7, at pressures up to 20 kbar and in magnetic fields up to 6T were measured.
Patent•
08 Mar 1983
TL;DR: In this paper, a magnetic sensor is constructed by two magnetoresistive elements and a conductive layer arranged there between for applying a magnetic bias to the sensor's output, and the second layer is used to cancel an effect of the external magnetic field by feeding back a differential output derived from the first magnetic sensor.
Abstract: A magnetic detection apparatus for use in an encoder includes a first magnetic sensor for detecting an external magnetic field and a second magnetic sensor for detecting a signal magnetic field. The first magnetic sensor is constructed by two magnetoresistive elements and a conductive layer arranged therebetween for applying a magnetic bias thereto. The second magnetic sensor is constructed by two magnetoresistive elements, first conductive layer arranged therebetween for applying a magnetic bias thereto and second conductive layer arranged on one side of two magnetoresistive elements for canceling an effect of the external magnetic field by feeding back a differential output derived from the first magnetic sensor thereto. In such a construction, it is possible to derive from the second magnetic sensor only a signal representing the signal magnetic field without being affected by the external magnetic field.
TL;DR: In this article, the angular dependence of the high field magnetoresistance anomaly in graphite is reported, consistent with the functional form for the phase boundary of a charge density wave transition suggested by Yoshioka and Fukuyama.
Abstract: : The angular dependence of the high field magnetoresistance anomaly in graphite is reported. The observed angular dependence is consistent with the functional form for the phase boundary of a charge density wave transition suggested Yoshioka and Fukuyama. Sharp periodic features in the resistivity occurring after the onset of the anomaly are reported.
TL;DR: In this paper, the Hall effect and magnetoresistance of four tin-doped bismuth samples in the temperature range 4.2-300K and in magnetic fields up to 6 T have been made.
Abstract: Measurements of the Hall effect and magnetoresistance of four tin-doped bismuth samples in the temperature range 4.2-300K and in magnetic fields up to 6 T have been made. The resistivity data are converted to conductivities. These are reported and used to evaluate the temperature dependence of the excess carrier density and of the thermopower. The evaluation is performed with the Fermi energy as the only adjustable parameter within the pseudo-parabolic model which the authors have previously introduced. The excess carrier density is found to decrease with temperature, and this feature is used to analyse the data in terms of an acceptor energy level. A relation valid for all samples is found between this level and the Fermi level. For the thermopower agreement is found between the calculated values and the experimental ones reported in the literature.
TL;DR: In this paper, the authors measured the low-temperature (0.02
Abstract: The authors have measured the low-temperature (0.02
TL;DR: In this paper, the resistance of a HgTe-CdTe superlattice of layer thickness 110 \AA{}/220 ǫ-AA{] shows logarithmic behavior with respect to temperature below 30 K. The field-parallel and field-perpendicular magnetoresistance clearly distinguish between the orbital and spin-dependent scattering mechanisms.
Abstract: The resistance of a HgTe-CdTe superlattice of layer thickness 110 \AA{}/220 \AA{} shows logarithmic behavior with respect to temperature below 30 K. The field-parallel and field-perpendicular magnetoresistance clearly distinguish between the orbital and spin-dependent scattering mechanisms, and confirm two-dimensional behavior.
TL;DR: In this article, the magnetic field induced nonmetal-metal transition was investigated in terms of the theory of an acceptor state modified by the exchange interaction between holes and Mn ++ ions.
Abstract: Transverse and longitudinal magnetoresistance of p-type Hg 1−x Mn x Te crystals (x=0.081,0.098,0.11) were investigated in the temperature range 1.4K–300K and in magnetic fields up to 7T. In the extrinsic and impurity conduction regime a strong negative magnetoresistance was observed. An experimental evidence for the magnetic field induced nonmetal-metal transition was obtained. The effects are discussed in terms of the theory of an acceptor state modified by the exchange interaction between holes and Mn ++ ions [1]. A role of the bound magnetic polaron localized on acceptor centre is also considered [2].
TL;DR: In this article, the effect of stress, temper, and reanneal on the residual resistance ratio (RRR) and magnetoresistance of several hundred samples of oxygen-free copper from many sources was investigated.
Abstract: Oxygen-free copper is the most common material used for stabilizing practical superconductors. This type of copper may show residual resistance ratios (RRR) that vary from 50 to 700 in the full soft condition. Knowledge of the exact RRR value is often essential for optimum system design. We have investigated the effect of stress, temper, and reanneal on the RRR and magnetoresistance of several hundred samples of oxygen-free copper from many sources. In this paper we describe the program and present a sampling of the results obtained to date.
TL;DR: In this paper, the advantages and disadvantages of different ways of linearization, such as bias filed, inclined elements or barber poles, are compared for sensors, since they allow characteristics with positive and negative slope which may be combined in a bridge circuit.
TL;DR: In this paper, the effects of electron-electron interaction on magnetoresistance in the Anderson-localized regime were investigated and the correlation of the interaction effects on the variable range hopping in the absence and presence of a magnetic field was clarified.
Abstract: Magnetoresistance in the Anderson-localized regime is calculated by the percolation method, with a particular purpose of investigating the effects of electron-electron interaction on it. It is predicted that the interplay of the intrastate interaction and the energy dependence of localization lengths gives rise to the competition of positive and negative contributions in the field dependence of the magnetoresistance. Further, combined with the interstate interactions, the temperature change in the magnetoresistance of ITTaS2 and its alloy systems is explained satisfactorily. Finally the correlation of the interaction effects on the variable range hopping in the absence and presence of a magnetic field is clarified.
Patent•
09 Jul 1983
TL;DR: In this paper, a magnetic head suitable for reproduction of short-wavelength and longwavelength recording and to reduce a contour effect by forming a magnetic recording medium facing surface of a bulky magnetic material with high magnetic permeability to sufficient length in a track direction was obtained.
Abstract: PURPOSE:To obtain a magnetic head suitable for reproduction of short-wavelength and long-wavelength recording and to reduce a contour effect by forming a magnetic recording medium facing surface of a bulky magnetic material with high magnetic permeability to sufficient length in a track direction. CONSTITUTION:In a groove 34 made in the surface of the bulky magnetic material 30 with high magnetic permeability, a high magnetic permeability material 36 is flattened with a nonmagnetic material 35 between while forming a surface nearly equal in level to the surface of said material 30, and on the surface of the material 30, a bulky magnetic material 30' with high magnetic permeability is arranged through a nonmagnetic film 31 for specifying a gap while coupling magnetically and tightly with the embedded magnetic material 36 with high magnetic permeability. A magnetic head of said structure has the magnetic recording medium facing surface formed of the bulky magnetic material with high magnetic permeability, so it is made sufficiently long in the track direction, so enough sensitivity for even long-wavelength recording is obtained.