Transport measurements in annealed single crystal tellurium

1970 ◽  
Vol 48 (24) ◽  
pp. 3038-3046 ◽  
Author(s):  
C. H. Champness ◽  
A. L. Kipling
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Single Crystal ◽  
Room Temperature ◽  
Small Diameter ◽  
Impurity Scattering ◽  
Czochralski Method ◽  
Liquid Nitrogen Temperature ◽  
Carrier Analysis ◽  
The Magnetic Field

Single crystal samples of tellurium obtained from small diameter ingots, specially grown by the Czochralski method from a melt of the purified element, were studied by measuring the electrical conductivity (σ), Hall coefficient (RH), and transverse magnetoresistance (Δρ/ρ0). As a result of annealing and etching, the Hall mobility (RHσ) and Δρ/ρ0 were substantially increased in the samples at liquid nitrogen temperature, while RH was slightly decreased. The samples were completely intrinsic above 250 °K and at room temperature Δρ/ρ0 was strictly proportional to the square of the magnetic field. Like RH and σ at this temperature, it was also independent of sample history. Two-carrier analysis at room temperature gave electron and hole mobilities of 1890 and 790 cm2 V−1 s−1 respectively. At 77 °K, Δρ/ρ0 in the annealed and etched samples was larger than expected for a simple one-carrier model with a mixture of lattice and impurity scattering.

scholarly journals Colossal Negative Magnetoresistance Effect in a La1.37Sr1.63Mn2O7 Single Crystal Grown by Laser-Diode-Heated Floating-Zone Technique

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 547
Author(s):  
Si Wu ◽  
Yinghao Zhu ◽  
Junchao Xia ◽  
Pengfei Zhou ◽  
Haiyong Ni ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Laser Diode ◽  
Room Temperature ◽  
Floating Zone ◽  
Magnetoresistance Effect ◽  
X Ray ◽  
Mr Effect ◽  
Distinct Features ◽  
The Magnetic Field

We have grown La 1.37 Sr 1.63 Mn 2 O 7 single crystals with a laser-diode-heated floating-zone furnace and studied the crystallinity, structure, and magnetoresistance (MR) effect by in-house X-ray Laue diffraction, X-ray powder diffraction, and resistance measurements. The La 1.37 Sr 1.63 Mn 2 O 7 single crystal crystallizes into a tetragonal structure with space group I4/mmm at room temperature. At 0 T, the maximum resistance centers around ∼166.9 K. Below ∼35.8 K, it displays an insulating character with an increase in resistance upon cooling. An applied magnetic field of B = 7 T strongly suppresses the resistance indicative of a negative MR effect. The minimum MR value equals −91.23% at 7 T and 128.7 K. The magnetic-field-dependent resistance shows distinct features at 1.67, 140, and 322 K, from which we calculated the corresponding MR values. At 14 T and 140 K, the colossal negative MR value is down to −94.04(5)%. We schematically fit the MR values with different models for an ideal describing of the interesting features of the MR value versus B curves.

A borehole induction procedure for investigating electrical conductivity structure within the broad vicinity of a hole

Geophysics ◽  
1981 ◽  
Vol 46 (1) ◽  
pp. 65-67 ◽  
Author(s):  
M. H. Worthington ◽  
A. Kuckes ◽  
M. Oristaglio
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Small Diameter ◽  
Effective Cross Section ◽  
Induction Procedure ◽  
Diameter Hole ◽  
Conductivity Structure ◽  
Metal Frame ◽  
The Magnetic Field ◽  
Broad Region

A field test was carried out of a controlled‐source induction procedure in which a source loop was positioned on the surface of the ground encircling a borehole, and the horizontal component of the magnetic field was measured within the hole. The problem of measuring the component of an alternating magnetic field at right angles to a small diameter hole was overcome by the construction of a μ‐metal frame for the induction coil that greatly increased the effective cross‐section of the coil. Data obtained with this configuration of source and receiver are dependent upon the electrical conductivity of the ground within a broad region around the hole. The method is effective in providing constraints on the location and distribution of regions of anomalous electrical conductivity which are not revealed by the drilling operation. These conclusions are supported by theoretical estimates of the magnetic field that would result from known conductivity distributions obtained using finite element techniques.

scholarly journals The change of electrical conductivity in strong magnetic fields. Part I. —Experimental results

1929 ◽  
Vol 123 (791) ◽  
pp. 292-341 ◽  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Magnetic Fields ◽  
Room Temperature ◽  
Linear Part ◽  
Strong Magnetic Fields ◽  
Other Substances ◽  
Different Temperatures ◽  
Weak Fields ◽  
The Magnetic Field

In a recent paper the author described experiments on the change of resistance of bismuth crystals in magnetic fields up to 300,000 gauss. In agreement with previous investigators it was found that the resistance of bismuth in weak fields increases in proportion to the square of the magnetic field, and in stronger fields follows a linear law, the increase of resistance being proportional to the magnetic field up to fields of 300 kilogauss. It was further found that this linear part of the change of resistance is, in most cases, independent of the orientation of the crystal in the magnetic field, and also of the degree of perfection of the crystal. This suggests that we are concerned with an atomic phenomenon. On studying several other substances it was found that the increase of resistance, although on a much smaller scale, is similar to that observed in bismuth, following first the square law and in fields above 60 to 100 kilogauss a linear law. This has led to a systematic study of the elements throughout the periodic table. About 35 different metals have been investigated at different temperatures, varying from room temperature to the temperature of liquid nitrogen, and the law of change of resistance mentioned above is found to be general for all.

EPR Study of VO2+ and Cr3+ in Li2SO4 · H2O Single Crystal

1997 ◽  
Vol 52 (11) ◽  
pp. 765-770 ◽  
Author(s):  
F. Çelik ◽  
F. Köksal ◽  
İ. Kartal ◽  
H. Gümüş
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Room Temperature ◽  
Charge Compensation ◽  
Spin Hamiltonian ◽  
Temperature Analysis ◽  
X Band ◽  
Superhyperfine Interaction ◽  
Hamiltonian Parameters ◽  
The Magnetic Field

Abstract A single crystal X-band EPR study of VO2+ and Cr3+ in Li2SO4 • H2O was carried out at room temperature. Analysis of the spectra indicates that VO2+ substitutes for Li+ and that there are two magnetically inequivalent Li+ sites. The charge compensation occurs by removal of a neighboring Li+ . The principal values of the g and A tensors of the spin Hamiltonian for the two sites were determined. Superhyperfine interaction of the 3d1 electron of VO2+ with the neighboring water protons in the unit cell was observed and found to be between 0 and 0.5 mT, depending on the orientation of the magnetic field. Two magnetically different sites were also observed for Cr3+ , and the results were explained by a rhombic spin Hamiltonian. The Hamiltonian parameters g, D, and E were determined. It is concluded that VO2+ and Cr3+ enter into the Li+ places and the charge is compensated by a Li+ vacancy in the VO2+ case and proton vacancies in the Cr3+ case.

Investigating flexible textile-based coils for wireless charging wearable electronics

2019 ◽  
Vol 50 (3) ◽  
pp. 333-345 ◽  
Author(s):  
Danmei Sun ◽  
Meixuan Chen ◽  
Symon Podilchak ◽  
Apostolos Georgiadis ◽  
Qassim S Abdullahi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Electromagnetic Field ◽  
Electric Field ◽  
Dimensional Stability ◽  
Screen Printing ◽  
Wearable Electronics ◽  
Wireless Charging ◽  
The Magnetic Field ◽  
Screen Printed

Smart and interactive textiles have been attracted great attention in recent years. This research explored three different techniques and processes in developing textile-based conductive coils that are able to embed in a garment layer. Coils made through embroidery and screen printing have good dimensional stability, although the resistance of screen printed coil is too high due to the low conductivity of the print ink. Laser cut coil provided the best electrical conductivity; however, the disadvantage of this method is that it is very difficult to keep the completed coil to the predetermined shape and dimension. The tested results show that an electromagnetic field has been generated between the textile-based conductive coil and an external coil that is directly powered by electricity. The magnetic field and electric field worked simultaneously to complete the wireless charging process.

scholarly journals Hydromagnetic dynamos in rotating spherical fluid shells in dependence on the Prandtl number, density stratification and electromagnetic boundary conditions

2014 ◽  
Vol 44 (4) ◽  
pp. 293-312 ◽  
Author(s):  
Tomáš Šoltis ◽  
Ján Šimkanin
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Magnetic Fields ◽  
Prandtl Number ◽  
Inner Core ◽  
Polar Regions ◽  
Number Density ◽  
Magnetic Diffusion ◽  
Spherical Fluid ◽  
The Magnetic Field

Abstract We present an investigation of dynamo in a simultaneous dependence on the non-uniform stratification, electrical conductivity of the inner core and the Prandtl number. Computations are performed using the MAG dynamo code. In all the investigated cases, the generated magnetic fields are dipolar. Our results show that the dynamos, especially magnetic field structures, are independent in our investigated cases on the electrical conductivity of the inner core. This is in agreement with results obtained in previous analyses. The influence of non-uniform stratification is for our parameters weak, which is understandable because most of the shell is unstably stratified, and the stably stratified region is only a thin layer near the CMB. The teleconvection is not observed in our study. However, the influence of the Prandtl number is strong. The generated magnetic fields do not become weak in the polar regions because the magnetic field inside the tangent cylinder is always regenerated due to the weak magnetic diffusion.

How the Magnetic Field Impacts the Chiroptical Activities of Helical Copper Enantiomers

2021 ◽  
Author(s):  
jialu wu ◽  
Bo Li ◽  
Hong Wang ◽  
Ying Zhen Lai ◽  
Yue Ye ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
Thermogravimetric Analysis ◽  
Single Crystal ◽  
Structure Analysis ◽  
Chiral Ligands ◽  
X Ray ◽  
The Magnetic Field

A pair of enantiomers {[Cu(L-pro)(L-tyr)]·2H2O}n (L-1) and {[Cu(D-pro)(D-tyr)]·2H2O}n (D-1) based on the chiral ligands L/D-proline and L/D-tyrosine were synthesized and investigated by single-crystal X-ray structure analysis, IR, thermogravimetric analysis, solid-state...

scholarly journals Magnetic properties of cobalt microwires measured by piezoresistive cantilever magnetometry

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
G. Tosolini ◽  
J. M. Michalik ◽  
R. Córdoba ◽  
J. M. de Teresa ◽  
F. Pérez-Murano ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Room Temperature ◽  
Signal To Noise Ratio ◽  
Static Deflection ◽  
Magnetic Structures ◽  
Dual Beam ◽  
Piezoresistive Cantilevers ◽  
Good Signal ◽  
The Magnetic Field

AbstractWe present the magnetic characterization of cobalt wires grown by focused electron beam-induced deposition (FEBID) and studied using static piezoresistive cantilever magnetometry. We have used previously developed high force sensitive submicron-thick silicon piezoresistive cantilevers. High quality polycrystalline cobalt microwires have been grown by FEBID onto the free end of the cantilevers using dual beam equipment. In the presence of an external magnetic field, the magnetic cobalt wires become magnetized, which leads to the magnetic field dependent static deflection of the cantilevers. We show that the piezoresistive signal from the cantilevers, corresponding to a maximum force of about 1 nN, can be measured as a function of the applied magnetic field with a good signal to noise ratio at room temperature. The results highlight the flexibility of the FEBID technique for the growth of magnetic structures on specific substrates, in this case piezoresistive cantilevers.

CRITICAL FIELD AND MAGNETORESISTANCE OF SINGLE CRYSTAL TmNi2B2C

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3715-3717 ◽  
Author(s):  
D. G. NAUGLE ◽  
K. D. D. RATHNAYAKA ◽  
K. CLARK ◽  
P. C. CANFIELD
Keyword(s):  
Magnetic Field ◽  
Transition Temperature ◽  
Single Crystal ◽  
Critical Field ◽  
Superconducting Transition Temperature ◽  
Magnetic Transition ◽  
Upper Critical Field ◽  
Superconducting Transition ◽  
Large Anisotropy ◽  
The Magnetic Field

In-plane resistance as a function of magnitude and direction of the magnetic field and the temperature has been measured for TmNi2B2C from above the superconducting transition temperature at 10.7 K to below the magnetic transition TN=1.5 K. The superconducting upper critical field HC2(T) exhibits a large anisotropy and structure in the vicinity of TN. The magnetoresistance above TC is large and changes sign as the direction of the magnetic field is rotated from in-plane to parallel with the c-axis.

The stability of viscous flow between rotating cylinders in the presence of a magnetic field

1953 ◽  
Vol 216 (1126) ◽  
pp. 293-309 ◽  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Viscous Flow ◽  
Thermal Instability ◽  
Horizontal Layer ◽  
Rotational Stability ◽  
Marginal Stability ◽  
Inhibiting Effect ◽  
The Stability ◽  
The Magnetic Field

In this paper the theory of the stability of viscous flow between two rotating coaxial cylinders which has been developed by Taylor, Jeffreys and Meksyn is extended to the case when the fluid considered is an electrical conductor and a magnetic field along the axis of the cylinders is present. A differential equation of order eight is derived which governs the situation in marginal stability; and a significant set of boundary conditions for the problem is formulated. The case when the two cylinders are rotating in the same direction and the difference ( d ) in their radii is small compared to their mean (R 0 ) is investigated in detail. A variational procedure for solving the underlying characteristic value problem and determining the critical Taylor numbers for the onset of instability is described. As in the case of thermal instability of a horizontal layer of fluid heated below, the effect of the magnetic field is to inhibit the onset of instability, the inhibiting effect being the greater, the greater the strength of the field and the value of the electrical conductivity. In both cases, the inhibiting effect of the magnetic field depends on the strength of the field ( H ), the density ( ρ ) and the coefficients of electrical conductivity ( σ ), kinematic viscosity ( v ) and magnetic permeability ( μ ) through the same non-dimensional combination Q =μ 2 H 2 d 2 σ/ pv ; however, the effect on rotational stability is more pronounced than on thermal instability. A table of the critical Taylor numbers for various values of Q is provided.

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