Spintronic logic circuit and device prototypes utilizing domain walls in ferromagnetic wires with tunnel junction readout

2015 ◽  
Author(s):  
J. A. Currivan-Incorvia ◽  
S. Siddiqui ◽  
S. Dutta ◽  
E. R. Evarts ◽  
C. A. Ross ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Domain Walls ◽  
Logic Circuit ◽  
Spintronic Logic

MAGNETIC RACE-TRACK — A NOVEL STORAGE CLASS SPINTRONIC MEMORY

2008 ◽  
Vol 22 (01n02) ◽  
pp. 117-118 ◽  
Author(s):  
STUART PARKIN
Keyword(s):  
Domain Wall ◽  
Tunnel Junction ◽  
Domain Walls ◽  
Magnetic Tunnel Junction ◽  
Domain Wall Motion ◽  
Wall Structure ◽  
Micromagnetic Simulations ◽  
Confining Potential ◽  
Current Pulses ◽  
Race Track

A proposal for a novel storage-class memory is described in which magnetic domains are used to store information in a "magnetic race-track".1 The magnetic race-track shift register storage memory promises a solid state memory with storage capacities and cost rivaling that of magnetic disk drives but with much improved performance and reliability. The magnetic race track is comprised of tall columns of magnetic material arranged perpendicularly to the surface of a silicon wafer. The domains are moved up and down the race-track by nanosecond long current pulses using the phenomenon of spin momentum transfer. The domain walls in the magnetic race-track are read using magnetic tunnel junction magnetoresistive sensing devices arranged in the silicon substrate. Recent progress in developing magnetic tunnel junction devices with giant tunneling magnetoresistance exceeding 350% at room temperature will be mentioned.2 Experiments exploring the current induced motion and depinning of domain walls in magnetic nano-wires with artificial pinning sites will be discussed. The domain wall structure, whether vortex or transverse, and the magnitude of the pinning potential is shown to have surprisingly little effect on the current driven dynamics of the domain wall motion.3 By contrast the motion of DWs under nanosecond long current pulses is surprisingly sensitive to their length.4 In particular, we find that the probability of dislodging a DW, confined to a pinning site in a permalloy nanowire, oscillates with the length of the current pulse, with a period of just a few nanoseconds. Using an analytical model and micromagnetic simulations we show that this behaviour is connected to a current induced oscillatory motion of the DW. The period is determined by the DW mass and the curvature of the confining potential. When the current is turned off during phases of the DW motion when the DW has enough momentum, there is a boomerang effect that can drive the DW out of the confining potential in the opposite direction to the flow of spin angular momentum. Note from Publisher: This article contains the abstract only.

The formation of 360° domain walls in magnetic tunnel junction elements

2000 ◽  
Vol 76 (6) ◽  
pp. 754-756 ◽  
Author(s):  
X. Portier ◽  
A. K. Petford-Long
Keyword(s):  
Tunnel Junction ◽  
Domain Walls ◽  
Magnetic Tunnel Junction

Complementary Spintronic Logic With Spin Hall Effect-Driven Magnetic Tunnel Junction

2015 ◽  
Vol 51 (11) ◽  
pp. 1-4 ◽  
Author(s):  
Wang Kang ◽  
Chentian Zheng ◽  
Youguang Zhang ◽  
Dafine Ravelosona ◽  
Weifeng Lv ◽  
...  
Keyword(s):  
Hall Effect ◽  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Spin Hall Effect ◽  
Spintronic Logic

scholarly journals Logic circuit prototypes for three-terminal magnetic tunnel junctions with mobile domain walls

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
J. A. Currivan-Incorvia ◽  
S. Siddiqui ◽  
S. Dutta ◽  
E. R. Evarts ◽  
J. Zhang ◽  
...  
Keyword(s):  
Domain Walls ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Logic Circuit

Magnetic Tunnel Junction-Based Spintronic Logic Units Operated by Spin Transfer Torque

2012 ◽  
Vol 11 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Xiaofeng Yao ◽  
Jonathan Harms ◽  
Andrew Lyle ◽  
Farbod Ebrahimi ◽  
Yisong Zhang ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spintronic Logic

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

Lorentz microscopy study of magnetic domain walls in Fe-Cr-Co alloys

1978 ◽  
Vol 36 (1) ◽  
pp. 462-463
Author(s):  
Yalcin Belli
Keyword(s):  
Domain Walls ◽  
Magnetic Domain ◽  
Microscopy Study ◽  
Ferromagnetic Phase ◽  
Stable Phase ◽  
Magnetic Domains ◽  
Lorentz Microscopy ◽  
Magnetic Hardening ◽  
Electron Microscopes ◽  
Co Alloys

Fe-Cr-Co alloys have great technological potential to replace Alnico alloys as hard magnets. The relationship between the microstructures and the magnetic properties has been recently established for some of these alloys. The magnetic hardening has been attributed to the decomposition of the high temperature stable phase (α) into an elongated Fe-rich ferromagnetic phase (α1) and a weakly magnetic or non-magnetic Cr-rich phase (α2). The relationships between magnetic domains and domain walls and these different phases are yet to be understood. The TEM has been used to ascertain the mechanism of magnetic hardening for the first time in these alloys. The present paper describes the magnetic domain structure and the magnetization reversal processes in some of these multiphase materials. Microstructures to change properties resulting from, (i) isothermal aging, (ii) thermomagnetic treatment (TMT) and (iii) TMT + stepaging have been chosen for this investigation. The Jem-7A and Philips EM-301 transmission electron microscopes operating at 100 kV have been used for the Lorentz microscopy study of the magnetic domains and their interactions with the finely dispersed precipitate phases.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

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