Effects of FM/NM Interfaces on Spin Accumulation in Free Layer of Pseudo-Spin-Valve Structure

2007 ◽  
Vol 998 ◽  
Author(s):  
Jiuning Hu ◽  
Min Ren ◽  
Lei Zhang ◽  
Ning Deng ◽  
Hao Dong ◽  
...  
Keyword(s):  
Spin Diffusion ◽  
Spin Valve ◽  
Spin Current ◽  
Spin Accumulation ◽  
Free Layer ◽  
Fixed Layer ◽  
Spacer Layer ◽  
Polarization Factor ◽  
Valve Structure ◽  
Parallel Configuration

ABSTRACTThe ferromagnetic/nonmagnetic (FM/NM) interfacial effects on the spin accumulation in the free layer were studied in a pseudo-spin-valve structure (PSVs) consisting of two FM layers separated by a NM spacer layer. We developed a spin current model for the current-induced magnetic switching (CIMS) effect based on the spin diffusion equations and appropriate boundary conditions, and derived a new formula for the spin-dependent electrochemical potentials that are related to the spin-dependent density of states. The results indicate that the spin accumulation in the free layer mainly depends on the interfacial spin asymmetry coefficient Ξ?which originates from the spin-dependent interfacial conductance. In the parallel (anti-parallel) configuration of the magnetization direction for the free and fixed layer, the positive (negative) electron current (electrons from the free layer to the fixed layer and vice versa) drives the spin current polarization factor at the interface between the top electrode and the free layer to vary from Ξ? (-Ξ?) to 0, while at the interface between the free layer and the spacer layer the spin current polarization factor vary from Ξ? (0) to Ξ?/2, which means the total spin current polarization factor in the free layer varies from 0 (Ξ?) to Ξ?/2. These results show that the anti-parallel configuration has a less critical switching current than that of the parallel configuration. Thus, we can design PSVs with symmetrical critical current based on the model.

Enhanced spin accumulation in nano-pillar-based lateral spin valve using spin reservoir effect

2022 ◽  
Author(s):  
Xiaomin Cui ◽  
Shaojie Hu ◽  
Takashi Kimura
Keyword(s):  
Spin Diffusion ◽  
Spin Injection ◽  
Spin Valve ◽  
Spin Current ◽  
Spin Valves ◽  
Pure Spin ◽  
Spin Accumulation ◽  
Spintronic Devices ◽  
High Bias ◽  
Angle Deposition

Abstract Lateral spin valves are ideal nanostructures for investigating spin-transport physics phenomena and promoting the development of future spintronic devices owing to dissipation-less pure spin current. The magnitude of the spin accumulation signal is well understood as a barometer for characterizing spin current devices. Here, we develop a novel fabrication method for lateral spin valves based on ferromagnetic nanopillar structures using a multi-angle deposition technique. We demonstrate that the spin-accumulation signal is effectively enhanced by reducing the lateral dimension of the nonmagnetic spin channel. The obtained results can be quantitatively explained by the confinement of the spin reservoir by considering spin diffusion into the leads. The temperature dependence of the spin accumulation signal and the influence of the thermal spin injection under a high bias current are also discussed.

Effect of probe configuration on spin accumulation in lateral spin-valve structure

2005 ◽  
Vol 286 ◽  
pp. 88-90 ◽  
Author(s):  
T. Kimura ◽  
J. Hamrle ◽  
Y. Otani ◽  
K. Tsukagoshi ◽  
Y. Aoyagi
Keyword(s):  
Spin Valve ◽  
Spin Accumulation ◽  
Valve Structure

Manipulating Spin Current in the Magnetic Nanopillar

2007 ◽  
Vol 7 (1) ◽  
pp. 259-264 ◽  
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.

Influence of Au capping Layer on spin accumulation in a lateral spin-valve structure

2005 ◽  
Vol 41 (10) ◽  
pp. 2600-2602 ◽  
Author(s):  
T. Kimura ◽  
J. Hamrle ◽  
Y. Otani
Keyword(s):  
Spin Valve ◽  
Spin Accumulation ◽  
Capping Layer ◽  
Valve Structure

Sensitivity Dependence of the Planar Hall Effect Sensor on the Free Layer of the Spin-Valve Structure

2009 ◽  
Vol 45 (6) ◽  
pp. 2374-2377 ◽  
Author(s):  
T.Q. Hung ◽  
S.J. Oh ◽  
B.D. Tu ◽  
N.H. Duc ◽  
L.V. Phong ◽  
...  
Keyword(s):  
Hall Effect ◽  
Spin Valve ◽  
Free Layer ◽  
Planar Hall Effect ◽  
Hall Effect Sensor ◽  
Valve Structure

Insertion of a Specular Reflective and Transmissive Nano-Oxide Layer into Giant Magnetoresistance Spin-Valve Structure

2006 ◽  
Vol 6 (11) ◽  
pp. 3483-3486
Author(s):  
Chunghee Nam ◽  
Youngman Jang ◽  
Ki-Su Lee ◽  
Jungjin Shim ◽  
B. K. Cho
Keyword(s):  
Oxide Layer ◽  
Sheet Resistance ◽  
Giant Magnetoresistance ◽  
Spin Valve ◽  
Interlayer Coupling ◽  
Free Layer ◽  
Uniform Layer ◽  
Nano Oxide ◽  
Valve Structure ◽  
Current Shunt

We have studied the influence of the insertion of a nano-oxide layer (NOL) into a magnetic GMR spin-valve. It was found that the spin-valve with NOL has a higher GMR ratio than that of the normal spin-valve without NOL. Naturally formed NOL without vacuum break shows a uniform layer, which effectively suppresses the current shunt, resulting in the reduction of the sheet resistance of GMR. The NOL spin-valve also shows a lower interlayer coupling (Hin) than that of the optimal normal spin-valve, which is consistent with AFM measurement showing lower roughness of NOL formed CoFe surface. Based on the advantage of NOL, we succeeded in lowering Hin while maintaining GMR ratio by insertion of NOL inside the CoFe free layer, where the free layer consists of CoFe/NOL/CoFe/NOL/Capping layer.

Longitudinal and transverse spin current absorptions in a lateral spin-valve structure

2012 ◽  
Vol 86 (10) ◽  
Author(s):  
S. Nonoguchi ◽  
T. Nomura ◽  
T. Kimura
Keyword(s):  
Spin Valve ◽  
Spin Current ◽  
Transverse Spin ◽  
Valve Structure
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