Coexistence of Large Voltage Controlled Magnetic Anisotropy, Large Surface Anisotropy, and Large TMR by a new MTJ structure having MgO/CoFeB/Ir/CoFeB.

2018 ◽  
Author(s):  
S. Oikawa ◽  
Y. Saito ◽  
H. Yoda ◽  
Y. Kato ◽  
A. Tiwari ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Surface Anisotropy

scholarly journals Route towards efficient magnetization reversal driven by voltage control of magnetic anisotropy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Roxana-Alina One ◽  
Hélène Béa ◽  
Sever Mican ◽  
Marius Joldos ◽  
Pedro Brandão Veiga ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Random Access ◽  
Low Power Consumption ◽  
Surface Anisotropy ◽  
Magnetization Dynamics ◽  
Storage Density ◽  
Switching Regime ◽  
Major Interest ◽  
Out Of Plane

AbstractThe voltage controlled magnetic anisotropy (VCMA) becomes a subject of major interest for spintronics due to its promising potential outcome: fast magnetization manipulation in magnetoresistive random access memories with enhanced storage density and very low power consumption. Using a macrospin approach, we carried out a thorough analysis of the role of the VCMA on the magnetization dynamics of nanostructures with out-of-plane magnetic anisotropy. Diagrams of the magnetization switching have been computed depending on the material and experiment parameters (surface anisotropy, Gilbert damping, duration/amplitude of electric and magnetic field pulses) thus allowing predictive sets of parameters for optimum switching experiments. Two characteristic times of the trajectory of the magnetization were analyzed analytically and numerically setting a lower limit for the duration of the pulses. An interesting switching regime has been identified where the precessional reversal of magnetization does not depend on the voltage pulse duration. This represents a promising path for the magnetization control by VCMA with enhanced versatility.

Magnetic Anisotropy of Crystalline Defects

1991 ◽  
Vol 231 ◽  
Author(s):  
B.M. Clemens ◽  
R.L. White ◽  
W.D. Nix ◽  
J.A. Bain
Keyword(s):  
Film Thickness ◽  
Magnetic Anisotropy ◽  
Strain Field ◽  
Coherency Strain ◽  
Misfit Dislocations ◽  
Surface Anisotropy ◽  
Crystalline Defects ◽  
Preferred Direction ◽  
Coherency Strains

AbstractWe consider the anisotropies due to coherency strains and the inilioliogcliotis stratlus associated with misfit dislocations, both of which give rise to anisotropy through maguctostrictive coupling. Coherency strains can give rise to anl apparent surface anisotrnpy due to the decrease in coherency strain with the film thickness. This anisotropy is comparable in magnitude to that observed experimentally for Fe [110] epitaxial thiut films on W [110]. The strain field associated with misfit dislocations produces a. surface anisotropy which is also comparable in magnitude to experimentally observed anisotropies. Dislocatioms along the inplane [001] and [110] directions both produce the same preferred direction of maguctization orientation.

scholarly journals Route Towards Efficient Magnetization Reversal Driven by Voltage Control of Magnetic Anisotropy

2021 ◽  
Author(s):  
Roxana-Alina One ◽  
Hélène Béa ◽  
Sever Mican ◽  
Marius Joldos ◽  
Pedro Veiga Brandao ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Random Access ◽  
Low Power Consumption ◽  
Surface Anisotropy ◽  
Magnetization Dynamics ◽  
Storage Density ◽  
Switching Regime ◽  
Major Interest ◽  
Out Of Plane

Abstract The voltage controlled magnetic anisotropy (VCMA) becomes a subject of major interest for spintronics due to its promising potential outcome: fast magnetization manipulation in magnetoresistive random access memories with enhanced storage density and very low power consumption. Using a macrospin approach, we carried out a thorough analysis of the role of the VCMA on the magnetization dynamics of nanostructures with out-of-plane magnetic anisotropy. Diagrams of the magnetization switching have been computed depending on the material and experiment parameters (surface anisotropy, Gilbert damping, duration/amplitude of electric and magnetic field pulses) thus allowing predictive sets of parameters for optimum switching experiments. Two characteristic times of the trajectory of the magnetization were analyzed analytically and numerically setting a lower limit for the duration of the pulses. An interesting switching regime has been identified where the precessional reversal of magnetization does not depend on the voltage pulse duration. This represents a promising path for the magnetization control by VCMA with enhanced versatility.

Perpendicular Magnetic Anisotropy of Pd/Co and Related Multilayers

1991 ◽  
Vol 231 ◽  
Author(s):  
S. Tsunashima ◽  
K. Nakamura ◽  
H. Takahashi ◽  
S. Fukatsu ◽  
S. Uchiyama
Keyword(s):  
Magnetic Anisotropy ◽  
Noble Metal ◽  
Crystal Orientation ◽  
Rf Sputtering ◽  
Perpendicular Magnetic Anisotropy ◽  
Multilayer Films ◽  
Surface Anisotropy ◽  
View Point ◽  
Magnetoelastic Energy ◽  
Magnetoelastic Surface

AbstractMultilayer films consists of noble metal (Pd, Pt, Cu, Au, PdSi) and transition metal(Co, Ni, PdCo, PtCo, CoZr) layers were prepared by rf sputtering method on glass and/or MgO single crystal substrates. The perpendicular magnetic anisotropy was examined in relation to the magnetostriction, lattice misfits, crystallinity and crystal orientations. The results suggest that the perpendicular magnetic anisotropy in noble metal/PdCo alloy multilayers originates from the magnetoelastic energy of the PdCo layers under a stress due to the lattice misfits. In both Pd/Co and Pd/Ni multilayers, the anisotropy was found to depend on the crystal orientation, and the dependence is discussed from the view point of the magnetoelastic surface anisotropy.

Magnetic Anisotropy of Epitaxial Co/Pt Superlattices

1991 ◽  
Vol 231 ◽  
Author(s):  
C.J. Chien ◽  
B.M. Clemens ◽  
S.B. Hagstrom ◽  
R.F.C. Farrow ◽  
C.H. Lee ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Easy Axis ◽  
Magnetocrystalline Anisotropy ◽  
Structural Data ◽  
Magnetic Surface ◽  
Surface Anisotropy ◽  
Cross Sectional ◽  
Planar Defects ◽  
Gaas Substrates ◽  
Transmission Electron

AbstractSelected orientations of epitaxial Co/Pt superlattices were grown on GaAs substrates in [001], [110], and [111] orientations using seeded epitaxy techniques. The microstructural and magnetic properties of Co/Pt superlattices are presented. The magnetic anisotropies of Co/Pt superlattices are found strongly dependent on the crystallographic orientation of the growth axis. High-resolution cross-sectional transmission electron microscopy (HRXTEM) investigation of the Co/Pt interfaces has revealed the presence of a large number of planar defects in the [111] Co/Pt superlattice. HRXTEM shows that the interface of Co/Pt is wavy and is not atomically abrupt. These findings suggest that models for the magnetic anisotropy should not be based on idealized, chemically abrupt interfaces but should incorporate magnetocrystalline anisotropy in the alloy region. We propose a model for the magnetic anisotropy based on the N6el magnetic surface anisotropy and the existence of defects in the alloy region. The easy axis of the magnetic anisotropy predicted by the model agrees with the magnetic and structural data for the superlattices.

TEM Study of Co/Pd and Co/Au Multilayers

1993 ◽  
Vol 51 ◽  
pp. 1036-1037
Author(s):  
A.E.M. De Veirman ◽  
F.J.G. Hakkens ◽  
W.M.J. Coene ◽  
F.J.A. den Broeder
Keyword(s):  
Magnetic Anisotropy ◽  
Ion Beam ◽  
Perpendicular Magnetic Anisotropy ◽  
Optical Recording ◽  
Magnetic Multilayer ◽  
Ion Beam Sputtering ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Beam Sputtering ◽  
Substrate Temperatures

There is currently great interest in magnetic multilayer (ML) thin films (see e.g.), because they display some interesting magnetic properties. Co/Pd and Co/Au ML systems exhibit perpendicular magnetic anisotropy below certain Co layer thicknesses, which makes them candidates for applications in the field of magneto-optical recording. It has been found that the magnetic anisotropy of a particular system strongly depends on the preparation method (vapour deposition, sputtering, ion beam sputtering) as well as on the substrate, underlayer and deposition temperature. In order to get a better understanding of the correlation between microstructure and properties a thorough cross-sectional transmission electron microscopy (XTEM) study of vapour deposited Co/Pd and Co/Au (111) MLs was undertaken (for more detailed results see ref.).The Co/Pd films (with fixed Pd thickness of 2.2 nm) were deposited on mica substrates at substrate temperatures Ts of 20°C and 200°C, after prior deposition of a 100 nm Pd underlayer at 450°C.

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