Enhanced Spin Accumulation in Semiconductor at Room Temperature Using Ni0.65Zn0.35Fe2O4(NZFO) as Spin Injector in NZFO/MgO/p-Si Device

In this article, the fabrication of a Ni0.65Zn0.35Fe2O4/MgO/p-Si heterostructure device has been optimized using the pulsed laser deposition (PLD) technique, and a detailed investigation of its structural, electrical, and magnetic features has been performed experimentally. The electronic and magneto-transport characteristics have been explored in the temperature range of 100–300 K. The current-voltage (I-V) characteristics of the heterojunction have been recorded, which displayed an excellent rectifying magnetic tunnel diode-like behavior throughout that temperature regime. The application of an external magnetic field parallel to the plane of the NZFO film causes the current (I) across the junction to decrease, clearly indicating positive junction magnetoresistance (JMR) of the heterostructure. The root of displaying positive magnetoresistance in our heterojunction has been well justified using the standard spin injection model. The electrical injection of spin-polarized carriers and its accumulation and detection in a p-Si channel have been demonstrated using the NZFO/MgO tunnel contact using a three-terminal (3-T) Hanle device. The parameters such as spin lifetime (99 ps), spin diffusion length (276 nm), and spin polarization (0.44) have been estimated from the Hanle curve detected in our heterostructure at room temperature, making the Ni0.65Zn0.35Fe2O4/MgO/p-Si device a very favorable promising junction structure in the field of spintronics for several device appliances in the future.

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Eﬀective modulation of spin accumulation using a ferromagnetic/nonmagnetic bilayer spin channel

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac34aa ◽

2021 ◽

Author(s):

Taisei Ariki ◽

Tatsuya Nomura ◽

Kohei Ohnishi ◽

Takashi Kimura

Keyword(s):

Spin Injection ◽

Spin Valve ◽

Transverse Spin ◽

Spin Accumulation ◽

Spin Channel ◽

Relative Angle ◽

Channel Layer ◽

Spin Polarized ◽

Resistance Model ◽

Large Spin

Abstract A lateral spin valve consisting of highly spin-polarized CoFeAl electrodes with a CoFeAl/Cu bilayer spin channel has been developed. Despite a large spin absorption into the CoFeAl capping channel layer, an eﬃcient spin injection and detection using the CoFeAl electrodes enable us to observe a clear spin valve signal. We demonstrate that the nonlocal spin accumulation signal is signiﬁcantly modulated depending on the relative angle of the magnetizations between the spin injector and absorber. The observed modulation phenomena is explained by the longitudinal and transverse spin absorption eﬀects into the CoFeAl channel layer with the spin resistance model.

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Spin injection and detection in p-Si channel using highly spin polarized Heusler alloy Co45Ni5Cr25Al25/MgO tunnel contact

10.1063/1.4980735 ◽

2017 ◽

Author(s):

Uddipta Kar ◽

J. Panda ◽

T. K. Nath

Keyword(s):

Heusler Alloy ◽

Spin Injection ◽

Tunnel Contact ◽

Spin Polarized ◽

Spin Injection And Detection

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Determination of the spin diffusion length in germanium by spin optical orientation and electrical spin injection

Journal of Physics D Applied Physics ◽

10.1088/0022-3727/49/42/425104 ◽

2016 ◽

Vol 49 (42) ◽

pp. 425104 ◽

Cited By ~ 4

Author(s):

C Rinaldi ◽

S Bertoli ◽

M Asa ◽

L Baldrati ◽

C Manzoni ◽

...

Keyword(s):

Spin Diffusion ◽

Diffusion Length ◽

Spin Injection ◽

Optical Orientation ◽

Spin Diffusion Length ◽

Electrical Spin

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Manipulating Spin Current in the Magnetic Nanopillar

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.18021 ◽

2007 ◽

Vol 7 (1) ◽

pp. 259-264 ◽

Cited By ~ 2

Author(s):

T. Yang ◽

A. Hirohata ◽

T. Kimura ◽

Y. Otani

Keyword(s):

Layer Thickness ◽

Spin Relaxation ◽

Spin Diffusion ◽

Diffusion Length ◽

Ferromagnetic Layer ◽

Spin Current ◽

Spin Accumulation ◽

Magnetization Switching ◽

Capping Layer ◽

Spin Diffusion Length

Because of the capability to switch the magnetization of a nanoscale magnet, the spin transfer effect is critical for the application of magnetic random access memory. For this purpose, it is important to enhance the spin current carried by the charge current. Calculations based on the diffusive spin-dependent transport equations reveal that the magnitude of spin current can be tuned by modifying the ferromagnetic layer and the spin relaxation process in the device. Increasing the ferromagnetic layer thickness is found to enhance both the spin current and the spin accumulation. On the other hand, a strong spin relaxation in the capping layer also increases the spin current but suppresses the spin accumulation. To demonstrate the theoretical results, nanopillar structures with the size of ∼100 nm are fabricated and the current-induced magnetization switching behaviors are experimentally studied. When the ferromagnetic layer thickness is increased from 3 nm to 20 nm, the critical switching current for the current-induced magnetization switching is significantly reduced, indicating the enhancement of the spin current. When the Au capping layer with a short spin-diffusion length replaces the Cu capping layer with a long spin-diffusion length, the reduction of the critical switching current is also observed.

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A DISCUSSION ON SPIN-POLARIZED QUASIPARTICLES INJECTION

International Journal of Modern Physics B ◽

10.1142/s0217979205028876 ◽

2005 ◽

Vol 19 (01n03) ◽

pp. 487-489

Author(s):

C. H. CAO ◽

M. YANG ◽

S. Z. YANG

Keyword(s):

Spin Diffusion ◽

Diffusion Length ◽

Ybco Film ◽

Current Injection ◽

Injection Efficiency ◽

Spin Polarized ◽

Spin Diffusion Length

The spin-polarized quasiparticles injection in YBCO film has been studied by means of current injection into NdSrMnO / SrTiO / YBaCuO heterostructures. Six injection junction windows are all 56μm wide, but 80μm, 40μm, 20μm, 10μm, 5μm, and 2μm long, respectively. Under I inj=0.5 Ma , injection efficiency η increases gradually with the decrease of injection junction length L, but η hardly varies when L is less than 20ηm. ηmax is more than 6. These experiment results are related with the spin diffusion length of spin-polarized quasiparticles in a-b plane of YBCO film. "Current-adding principle" would be used carefully to explain the experiment phenomena.

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NONLOCAL ELECTRONIC SPIN DETECTION, SPIN ACCUMULATION AND THE SPIN HALL EFFECT

International Journal of Modern Physics B ◽

10.1142/s021797920905290x ◽

2009 ◽

Vol 23 (11) ◽

pp. 2413-2438 ◽

Cited By ~ 43

Author(s):

SERGIO O. VALENZUELA

Keyword(s):

Hall Effect ◽

Spin Diffusion ◽

Spin Injection ◽

Spin Hall Effect ◽

Current Status ◽

Pure Spin ◽

Spin Accumulation ◽

Spin Currents ◽

Electrical Spin ◽

Spin Detection

In recent years, electrical spin injection and detection has grown into a lively area of research in the field of spintronics. Spin injection into a paramagnetic material is usually achieved by means of a ferromagnetic source, whereas the induced spin accumulation or associated spin currents are detected by means of a second ferromagnet or the reciprocal spin Hall effect, respectively. This article reviews the current status of this subject, describing both recent progress and well-established results. The emphasis is on experimental techniques and accomplishments that brought about important advances in spin phenomena and possible technological applications. These advances include, amongst others, the characterization of spin diffusion and precession in a variety of materials, such as metals, semiconductors and graphene, the determination of the spin polarization of tunneling electrons as a function of the bias voltage, and the implementation of magnetization reversal in nanoscale ferromagnetic particles with pure spin currents.

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Effect of Electric-Field on Spin Injection Efficiency in the Organic Semiconductors

Materials Science Forum ◽

10.4028/www.scientific.net/msf.852.704 ◽

2016 ◽

Vol 852 ◽

pp. 704-707

Author(s):

Yi Lin Mi ◽

Jiang Nan Gao

Keyword(s):

Electrical Conductivity ◽

Electric Field ◽

External Electric Field ◽

Organic Semiconductors ◽

Spin Diffusion ◽

Diffusion Length ◽

Spin Injection ◽

Injection Efficiency ◽

Conductivity Increase ◽

Spin Diffusion Length

The spin injection efficiency in the ferromagnet/ organic semiconductors system (FM/OSE) was studied under an external electric-field. It is found that the spin injection efficiency can be strongly influenced by the spin-dependent electrical conductivity and the downstream spin diffusion length of polarons. With the increase of external electric-field, the downstream spin diffusion length increases and makes the spin-dependent electrical conductivity increase, too. So the spin injection efficiency is enhanced. When the external electric-field increases from 1 to 10 mV/μm at T=80K, the spin injection efficiency increases about 20%. It seems that the downstream spin diffusion length is an significant factor to affect the spin injection efficiency in the FM/ OSE under an external electric-field.

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ELECTRICAL EXPRESSION OF SPIN ACCUMULATION IN FERROMAGNET/SEMICONDUCTOR STRUCTURES

Modern Physics Letters B ◽

10.1142/s021798490701395x ◽

2007 ◽

Vol 21 (23) ◽

pp. 1509-1529

Author(s):

ŁUKASZ CYWIŃSKI ◽

HANAN DERY ◽

PARIN DALAL ◽

L. J. SHAM

Keyword(s):

Schottky Barrier ◽

Bound States ◽

Spin Diffusion ◽

Spin Injection ◽

Logic Gate ◽

Scattering Problem ◽

Memory Cell ◽

Planar Geometry ◽

Magnetic Memory ◽

Spin Accumulation

We treat the spin injection and extraction via a ferromagnetic metal/semiconductor Schottky barrier as a quantum scattering problem. This enables the theory to explain a number of phenomena involving spin-dependent current through the Schottky barrier, especially the counter-intuitive spin polarization direction in the semiconductor due to current extraction seen in recent experiments. A possible explanation of this phenomenon involves taking into account the spin-dependent inelastic scattering via the bound states in the interface region. The quantum-mechanical treatment of spin transport through the interface is coupled with the semiclassical description of transport in the adjoining media, in which we take into account the in-plane spin diffusion along the interface in the planar geometry used in experiments. The theory forms the basis of the calculation of spin-dependent current flow in multi-terminal systems, consisting of a semiconductor channel with many ferromagnetic contacts attached, in which the spin accumulation created by spin injection/extraction can be efficiently sensed by electrical means. A three-terminal system can be used as a magnetic memory cell with the bit of information encoded in the magnetization of one of the contacts. Using five terminals we construct a reprogrammable logic gate, in which the logic inputs and the functionality are encoded in magnetizations of the four terminals, while the current out of the fifth one gives a result of the operation.

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Room-temperature spin transport in InAs nanowire lateral spin valve

RSC Advances ◽

10.1039/c6ra13516a ◽

2016 ◽

Vol 6 (79) ◽

pp. 75736-75740 ◽

Cited By ~ 2

Author(s):

Zhicheng Wang ◽

Dong Pan ◽

Le Wang ◽

Tingwen Wang ◽

Bing Zhao ◽

...

Keyword(s):

Room Temperature ◽

Spin Transport ◽

Spin Diffusion ◽

Diffusion Length ◽

Spin Valve ◽

Spintronic Devices ◽

Spin Diffusion Length ◽

Nanowire Device ◽

Large Spin

We report room temperature spin transport in an InAs nanowire device. A large spin signal of 35 kΩ and long spin diffusion length of 1.9 μm are achieved. We believe that these results open a practical way to design InAs NW based spintronic devices.

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