scholarly journals Electric readout of magnetic stripes in insulators

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yao Chen ◽  
Yuki Shiomi ◽  
Zhiyong Qiu ◽  
Tomohiko Niizeki ◽  
Maki Umeda ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Field Resistance ◽  
Superconducting Order Parameter ◽  
Nanometer Scale ◽  
Zero Field ◽  
Local Magnetization ◽  
Resistance Change ◽  
Analog Memory ◽  
Superconductor Film ◽  
Topological Configuration

AbstractIn superconductors, a topological configuration of the superconducting order parameter called a superconducting vortex carries magnetization. Such a magnetic topological object behaves like a minute particle generating a magnetic flux. Since the flux is localized with a nanometer scale, the vortex provides a nano-scale probe for local magnetic fields. Here we show that information of magnetic stripes in insulators can be read out by using vortices in an adjacent superconductor film as a probe. The orientation and width of magnetic micro stripes are both transcribed into resistance change of the superconductor through the modulation of vortex mobility affected by local magnetization. By changing the direction of external magnetic fields, zero-field resistance changes continuously according to the stripe orientation, and its modulation magnitude reaches up to 100%. The width of the stripes can also be estimated from the oscillatory magnetoresistance. Our results demonstrate a new possibility for non-volatile analog memory devices based on topological objects.

Strain, Anisotropy and Low Field Magnetoresistance Effect in Ultrathin Manganite Films

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3372-3375 ◽  
Author(s):  
H. S. Wang ◽  
Qi Li
Keyword(s):  
Magnetic Fields ◽  
Film Surface ◽  
Small Strain ◽  
Zero Field ◽  
Magnetoresistance Effect ◽  
Resistance Change ◽  
Strain Anisotropy ◽  
Low Field ◽  
Spin Scattering

We report low-field magnetoresistance (LFMR) of strained ultrathin Pr0.67Sr0.33MnO3 (PSMO) films. We observed very large LFMR, a factor of 7 of resistance change in zero-field-cooled sample at 80 K and 2000 Oe, in ultrathin PSMO films on LaAlO3 (LAO) (100). Samples with compressive (on (LAO), tensile (on SrTiO 3 (100)) and very small strain (on NdGaO 3 (110)) have been studied systematically and remarkable differences were observed. We also observed large LFMR anisotropy between magnetic fields applied parallel and perpendicular to the film surface. Our results demonstrated that strain and strain-induced spin scattering can result in large LFMR effect.

scholarly journals Observations of magnetic and kinetic helicity proxies

2012 ◽  
Vol 8 (S294) ◽  
pp. 13-24
Author(s):  
Hongqi Zhang
Keyword(s):  
Magnetic Field ◽  
Velocity Field ◽  
Magnetic Fields ◽  
Solar Atmosphere ◽  
Active Regions ◽  
Solar Dynamo ◽  
Magnetic Helicity ◽  
Vector Magnetograms ◽  
Topological Configuration ◽  
The Relationship

AbstractThe helicity is important to present the basic topological configuration of magnetic field in solar atmosphere. The distribution of magnetic helicity in solar atmosphere is presented by means of the observational (vector) magnetograms. As the kinetic helicity in the solar subatmosphere can be inferred from the velocity field based on the technique of the helioseismology and used to compare with the magnetic helicity in the solar atmosphere, the observational helicities provide the important chance for the confirmation on the generation of magnetic fields in the subatmosphere and solar dynamo models also. In this paper, we present the observational magnetic and kinetic helicity in solar active regions and corresponding questions, except the relationship with solar eruptive phenomena.

scholarly journals Effects of High Magnetic Fields on Phase Transformations in Amorphous Nd2Fe14B

2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Michael Kesler ◽  
Brandt Jensen ◽  
Lin Zhou ◽  
Olena Palasyuk ◽  
Tae-Hoon Kim ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Melt Spinning ◽  
Magnetic Behavior ◽  
Phase Evolution ◽  
High Magnetic Fields ◽  
Phase Identification ◽  
Zero Field ◽  
Transmission Electron ◽  
Size And Morphology ◽  
Applied Fields

We briefly summarize the results from a set of experiments designed to demonstrate the effects of high magnetic fields applied during thermal annealing of amorphous Nd2Fe14B produced through melt-spinning. A custom-built differential scanning calorimeter was used to determine the crystallization temperatures in zero-field and in applied fields of 20 kOe and 90 kOe, which guided subsequent heat treatments to evaluate phase evolution. X-ray diffraction was used for phase identification and transmission electron microscopy was employed for observation of the crystallite size and morphology. Magnetization measurements were also used to evaluate the resulting magnetic phases after thermomagnetic processing. While the applied magnetic fields do not appear to affect the crystallization temperature, significant effects on the kinetics of phase evolution are observed and correlated strongly to the magnetic behavior.

PROTON IRRADIATION INFLUENCE ON THE MAGNETIC PROPERTIES OF GMR-SVs

2014 ◽  
Vol 28 (04) ◽  
pp. 1450022 ◽  
Author(s):  
CONG YIN ◽  
DAN XIE ◽  
JIAN-LONG XU ◽  
TIAN-LING REN
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Radiation Dose ◽  
Proton Energy ◽  
Giant Magnetoresistance ◽  
Proton Irradiation ◽  
Magnetic Phase ◽  
Field Resistance ◽  
Zero Field ◽  
Magnetoresistance Ratio

In this paper, crystal and magnetic properties of proton irradiated giant magnetoresistance spin valves (GMR-SVs) were investigated based on Ta / NiFe / CoFe / Cu / CoFe / IrMn / Ta stack. GMR-SVs were fabricated by magnetron sputtering and irradiated by 5 MeV proton energy. After irradiation, the magnetic phase of GMR-SV core structures was not affected distinctly while the crystal structure of Ta changed with the radiation dose and dose rate. Degradation of the saturated magnetization and the magnetoresistance ratio was shown in the proton-irradiated samples from the magnetization hysteresis curves and the magnetoresistance measurements, which was explained from the change in the zero-field resistance and the exchange interaction.

scholarly journals Effect of magnetic fields on cryptochrome-dependent responses in Arabidopsis thaliana

2009 ◽  
Vol 6 (41) ◽  
pp. 1193-1205 ◽  
Author(s):  
Sue-Re Harris ◽  
Kevin B. Henbest ◽  
Kiminori Maeda ◽  
John R. Pannell ◽  
Christiane R. Timmel ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Arabidopsis Thaliana ◽  
Magnetic Fields ◽  
Low Frequency ◽  
Zero Field ◽  
Experimental Conditions ◽  
Replication Studies ◽  
Weak Magnetic Fields ◽  
Simultaneous Control ◽  
Independent Replication

The scientific literature describing the effects of weak magnetic fields on living systems contains a plethora of contradictory reports, few successful independent replication studies and a dearth of plausible biophysical interaction mechanisms. Most such investigations have been unsystematic, devoid of testable theoretical predictions and, ultimately, unconvincing. A recent study, of magnetic responses in the model plant Arabidopsis thaliana , however, stands out; it has a clear hypothesis—that seedling growth is magnetically sensitive as a result of photoinduced radical-pair reactions in cryptochrome photoreceptors—tested by measuring several cryptochrome-dependent responses, all of which proved to be enhanced in a magnetic field of intensity 500 μT. The potential importance of this study in the debate on putative effects of extremely low-frequency electromagnetic fields on human health prompted us to subject it to the ‘gold standard’ of independent replication. With experimental conditions chosen to match those of the original study, we have measured hypocotyl lengths and anthocyanin accumulation for Arabidopsis seedlings grown in a 500 μT magnetic field, with simultaneous control experiments at 50 μT. Additionally, we have determined hypocotyl lengths of plants grown in 50 μT, 1 mT and approximately 100 mT magnetic fields (with zero-field controls), measured gene ( CHS , HY5 and GST ) expression levels, investigated blue-light intensity effects and explored the influence of sucrose in the growth medium. In no case were consistent, statistically significant magnetic field responses detected.

scholarly journals Analog Video Magnetograms in Real Time

1971 ◽  
Vol 43 ◽  
pp. 76-83 ◽  
Author(s):  
R. C. Smithson ◽  
R. B. Leighton
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Magnetic Field ◽  
Solar Spectrum ◽  
Zeeman Splitting ◽  
The Other ◽  
Line Of Sight ◽  
Zero Field ◽  
The Sun ◽  
Solar Magnetic Fields

For many years solar magnetic fields have been measured by a variety of techniques, all of which exploit the Zeeman splitting of lines in the solar spectrum. One of these techniques (Leighton, 1959) involves a photographic subtraction of two monochromatic images to produce a picture of the Sun in which the line-of-sight component of the solar magnetic field appears as various shades of gray. In a magnetogram made by this method, zero field strength appears as neutral gray, while magnetic fields of one polarity or the other appear as lighter or darker areas, respectively. Figure 1 shows such a magnetogram.

Weakly open quantum dots: Magnetotransport spectroscopy and zero-field resistance peaks

1999 ◽  
Vol 47 (1-4) ◽  
pp. 89-93
Author(s):  
D.P. Pivin ◽  
R. Akis ◽  
A. Andresen ◽  
J.P. Bird ◽  
D. Vasileska ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Field Resistance ◽  
Zero Field ◽  
Open Quantum

scholarly journals Current Progress of Magnetoresistance Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 211
Author(s):  
Songlin Yang ◽  
Jin Zhang
Keyword(s):  
Magnetic Fields ◽  
Giant Magnetoresistance ◽  
Hard Disk Drives ◽  
Magnetic Storage ◽  
Resistance Change ◽  
Current Sensing ◽  
Position Sensing ◽  
Biomedical Sensing ◽  
Sensing Systems ◽  
Current Trends

Magnetoresistance (MR) is the variation of a material’s resistivity under the presence of external magnetic fields. Reading heads in hard disk drives (HDDs) are the most common applications of MR sensors. Since the discovery of giant magnetoresistance (GMR) in the 1980s and the application of GMR reading heads in the 1990s, the MR sensors lead to the rapid developments of the HDDs’ storage capacity. Nowadays, MR sensors are employed in magnetic storage, position sensing, current sensing, non-destructive monitoring, and biomedical sensing systems. MR sensors are used to transfer the variation of the target magnetic fields to other signals such as resistance change. This review illustrates the progress of developing nanoconstructed MR materials/structures. Meanwhile, it offers an overview of current trends regarding the applications of MR sensors. In addition, the challenges in designing/developing MR sensors with enhanced performance and cost-efficiency are discussed in this review.

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