Angular dependence of the magnetoresistance effect in a silicon based p–n junction device

Nanoscale ◽  
2014 ◽  
Vol 6 (8) ◽  
pp. 3978-3983 ◽  
Author(s):  
Tao Wang ◽  
Mingsu Si ◽  
Dezheng Yang ◽  
Zhong Shi ◽  
Fangcong Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Space Charge ◽  
Angular Dependence ◽  
Space Charge Region ◽  
Magnetoresistance Effect ◽  
Junction Device ◽  
Mr Effect ◽  
Silicon Based

Anisotropic MR effect is seen in a non-magnetic p–n junction due to the space charge region being modulated by an external magnetic field.

SPACE-CHARGE EFFECT IN UNINTENTIONALLY N-DOPED SILICON

2012 ◽  
Vol 26 (08) ◽  
pp. 1250048 ◽  
Author(s):  
KANKAN CONG ◽  
YANG JI
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Space Charge ◽  
Space Charge Effect ◽  
Charge Effect ◽  
Temperature Range ◽  
Ohmic Behavior ◽  
Current Voltage ◽  
Doped Silicon ◽  
High Bias

We report experimental results on current–voltage characteristics of Au-Ti/n-Si/Au-Ti devices made on unintentionally n-doped silicon, which depend dramatically on temperature and external magnetic field. While such devices show Ohmic behavior in the temperature range 154–300 K, space-charge effect dominates at high bias voltages in the temperature range 77–154 K. In the later case, external magnetic field may increase its breakdown voltage, thus inducing large positive magnetoresistance similar to those reported by other groups.

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.

Numerical investigation of influence of ionic space charge and flexoelectric polarization on measurements of elastic constants in nematic liquid crystals

2009 ◽  
Vol 17 (2) ◽  
Author(s):  
M. Buczkowska ◽  
G. Derfel ◽  
M. Konowalski
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
External Magnetic Field ◽  
Space Charge ◽  
Elastic Constants ◽  
High Concentration ◽  
Light Passing ◽  
The Magnetic Field

AbstractDeformations of nematic layers caused by magnetic field allow determination of the elastic constants of liquid crystal. In this paper, we simulated numerically the deformations of planar and homeotropic nematic layers. The flexoelectric properties of the nematic and presence of ions were taken into account. Our aim was to show the influence of flexoelectricity on the results of the real measurement of the elastic constants k33 and k11. In these simulations, we calculated the optical phase difference ΔΦ between the ordinary and extraordinary rays of light passing through the layer placed between crossed polarizers as a function of the magnetic field induction B. One of the elastic constants can be calculated from the magnetic field threshold for deformation. The ratio k33/k11 can be found by means of fitting theoretical ΔΦ(B) dependence to the experimental results. The calculations reveal that the flexoelectric properties influence the deformations induced by the external magnetic field. In the case of highly pure samples, this may lead to false results of measurement of the elastic constants ratio k33/k11. This influence can be reduced if the nematic material contains ions of sufficiently high concentration. These results show that the flexoelectric properties may play an important role, especially in well purified samples.

Magnetic Field Sensors based on Magnetoresistance Effect in Organic Semiconductor Sandwich Devices

2005 ◽  
Vol 906 ◽  
Author(s):  
Govindarajan Veeraraghavan ◽  
Ömer Mermer ◽  
Yugang Sheng ◽  
Tho Duc Nguyen ◽  
Thomas Lee Francis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Organic Semiconductor ◽  
Room Temperature ◽  
Experimental Characterization ◽  
Magnetoresistance Effect ◽  
Temperature Dependent ◽  
Magnetic Field Sensors ◽  
Mr Effect ◽  
Alternating Magnetic Fields

AbstractWe describe magnetic field sensors based on a recently discovered magnetoresistance (MR) effect in nonmagnetic organic semiconductor sandwich devices. The MR effect reaches up to 10% in a magnetic field of 10 mT at room temperature. We perform an extensive experimental characterization of this effect. We found that the MR effect is only weakly temperature dependent and does not depend on sign and direction of the applied magnetic field. We also measured the device response to alternating magnetic fields up to 100 kHz. To the best of our knowledge, the discovered MR effect is not adequately described by any of the MR mechanisms known to date.

scholarly journals Variation of Velocity of Ions in a Magnetized Plasma Sheath for Different Magnetic Field

2020 ◽  
Vol 6 (1) ◽  
pp. 25-29
Author(s):  
B.R. Adhikari ◽  
S. Basnet ◽  
H.P. Lamichhane ◽  
R. Khanal
Keyword(s):  
Magnetic Field ◽  
Space Charge ◽  
Space Charge Region ◽  
Normal Component ◽  
Maximum Amplitude ◽  
Plasma Sheath ◽  
Magnetized Plasma ◽  
Positive Space Charge ◽  
The Magnetic Field ◽  
Positive Space

The kinetic trajectory simulation method has been used to study ion velocity profile in a plasma sheath for varying magnetic field at fixed obliqueness. As the electrons have higher velocity compared to that of ions the wall is charged up negatively with respect to the core plasma. The negative potential then attracts the ions and repels electrons forming a thin positive space charge region in front of the wall. This positive space charge region, known as the ‘sheath’ separates the negatively charged wall from the quasineutral ‘presheath’ plasma. The ions moving towards the wall have to satisfy the Bohm criterion to ensure the stability of the overall plasma. The mean value as well as oscillation frequency of velocity of ions change as the magnetic field is varied from 1.5 to 10.5 mT. The maximum amplitude of normal component of velocity is almost independent of the magnetic field but the maximum amplitude of other components of velocity change and shows oscillating nature as the magnetic field changes.

scholarly journals ANGLE-DEPENDENT TRANSMISSION FOR VISIBLE LIGHT OF MAGNETIC GRANULAR THIN FILMS

2018 ◽  
Vol 54 (5A) ◽  
pp. 27
Author(s):  
Giap Van Cuong
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
External Magnetic Field ◽  
Visible Light ◽  
Angular Dependence ◽  
Incident Light ◽  
Granular Films ◽  
Photon Interaction ◽  
Surface Normal

      The transmission for visible light (T), with wavelengths from 560 to 695 nm, was investigated at various light incident angles of 0 ¸ 45 degree for the surface normal of samples (φ) as a function of Co contents for magnetic granular films Cox-(Al2O3)1-x, where x = 0.10 ¸ 0.45. This investigation was carried out under an external magnetic field fixed at 4 kOe to ensure for all the Co-granule magnetization being kept in a fixed incident light propagating direction. Results showed a rather remarkable angular dependence of T(φ) on the Co content for different wavelengths. It was attributed the behavior of this to be dependent on the so-called magnon-photon interaction.

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