Structural defects analysis versus spin polarized tunneling in Co2FeAl/MgO/CoFe magnetic tunnel junctions with thick MgO barriers

Gabor, M. S.; Tiuşan, C.; Petrişor, T.; Hehn, M.; Lu, Yuan; Snoeck, E.

doi:10.1016/j.jmmm.2013.07.028

Cited by 10 publications

(5 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Concerning the epitaxial Fe(001)/MgO MTJs, the impact of chemical and structural defects has been experimentally checked. It has been shown that volume defects in the barrier as misfit dislocations are detrimental for TMR [13][14][15][16]. Surprisingly, controlled contamination of the interface with carbon [17,18], or oxygen has been found to have small impact on TMR values (at zero voltage) [19,20].…”

Section: Introductionmentioning

confidence: 99%

Enhanced magnetoresistance by monoatomic roughness in epitaxial Fe/MgO/Fe tunnel junctions

Duluard

Bellouard

et al. 2015

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

Interfacial effects on spin and symmetry filtering in single-crystal Fe(001)/MgO/Fe magnetic tunnel junctions are investigated with the insertion of a Fe monoatomic step at the bottom MgO interface. After annealing, the atomically flat bottom electrode is covered by a fractional part of a Fe monoatomic layer resulting in two-dimensional Fe islands that are separated for low coverages and percolated above around half a monolayer. The magnetotransport properties of the junctions are studied as a function of this Fe sublayer coverage that is varied from 0 to 1 monolayer. Surprisingly, the magnetoresistance ratio exhibits a maximum for a coverage around half a monolayer. Tunneling spectroscopy experiments performed at low temperature allow relating this result to the decrease of the contribution of the interfacial resonance state to the conductance of the junction.

show abstract

Section: Introductionmentioning

confidence: 99%

Enhanced magnetoresistance by monoatomic roughness in epitaxial Fe/MgO/Fe tunnel junctions

Duluard

Bellouard

et al. 2015

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

show abstract

“…To get deeper in the spin depolarization mechanisms, we have performed combined structural analysis and magneto-transport experiments in variable temperature. 49 Our analysis, accomplished on samples with thick MgO barriers, where the density of extended structural defects is enhanced, demonstrates unambiguously the detrimental e®ects of mis¯tdislocations in a single crystal tunnel barrier on the spin polarization of tunneling electrons. Combining geometric phase analysis of High Resolution Cross Section Transmission Electron Microscopy experiments, 50 destroy the longitudinal and lateral coherence of the propagating Bloch functions.…”

Section: Magnetic Tunnel Junctions With Co 2 Feal Electrodes Propertiesmentioning

confidence: 57%

ELECTRONIC, STRUCTURAL AND MAGNETIC PROPERTIES OF Co₂FeAl THIN FILMS FOR POTENTIAL SPINTRONIC APPLICATIONS

Gabor

Belmeguenai²,

Zighem³

et al. 2014

SPIN

Self Cite

View full text Add to dashboard Cite

This paper presents an overview concerning the electronic, structural and magnetic properties of Co 2 FeAl (CFA) thin films. We first used ab initio calculations of the electronic structure in order to discuss the half-metallicity of this compound. Involving a correlated structural-magnetic analysis, we then illustrate, experimentally, the effect of the thickness as well as the annealing temperature on the magnetic and structural properties of CFA films epitaxially grown on MgO (001) single crystal substrates. The X-ray diffraction shows that in our samples having the CFA(001)[110]// MgO (001)[100] epitaxial relation, the chemical order is enhanced as the thickness and the annealing temperature (T a ) are increased. Ferromagnetic resonance measurements reveal further dynamic magnetic properties. The gyromagnetic factor, estimated at 29.2 GHz/T, is both thickness and annealing temperature independent. The in-plane anisotropy results from the superposition between a dominant fourfold symmetry term, as expected for cubic crystal symmetry of the alloy, and a small uniaxial term. The fourfold anisotropy decreases with increasing thickness and annealing temperature. The exchange stiffness constant is thickness independent but increases with T a . In addition, the effective magnetization varies linearly with T a and with the inverse CFA thickness. This is due to the presence of perpendicular uniaxial anisotropy, estimated around -1.8 erg/cm2 at T a = 600°C and 1.05 erg/cm2 at T a = 265°C, respectively. Frequency and angular dependences of the FMR linewidth show two magnon scattering and mosaicity contributions which depend on the CFA thickness and T a . A Gilbert damping coefficient as low as 0.0011 is found for samples annealed at 600°C. Finally, we illustrate that these films can be used as ferromagnetic electrodes in sputtered epitaxial magnetic tunnel junctions (MTJ) based on MgO (001) tunnel barriers. These MTJs show an improvable TMR ratio around 95% at room temperature.

show abstract

“…The full Heusler alloys crystallize in the structure L2 1 , and they have a stoichiometric composition of type X 2 YZ, where X and Y are transition metals and Z represents the nonmagnetic element of the groups III, IV, or V in the periodic table. In general, the Heusler alloys crystallize in cubic structures of the face-centered cubic Cobalt-based alloys (Co 2 YZ) [41] are theoretically predicted to have a semimetallic character at room temperature. Therefore, they present particular interest for tspin electronics applications.…”

Section: Heusler Alloysmentioning

confidence: 99%

“…Figure 1 shows the full Heusler alloys of type X 2 YZ structural characterization. Cobalt-based alloys (Co 2 YZ) [41] are theoretically predicted to have a semimetallic character at room temperature. Therefore, they present particular interest for tspin electronics applications.…”

Section: Heusler Alloysmentioning

confidence: 99%

Ab initio study of the structural, electronic, and magnetic properties of Co 2 FeGa and Co 2 FeSi and their future contribution to the building of quantum devices

Oumsalem¹,

Bourezig²,

Nabi³

et al. 2018

Turk J Elec Eng & Comp Sci

View full text Add to dashboard Cite

How small can an electronic device be and still function? How many atoms are needed for such device? At what point will the semiconductor fabrication technology be unable to construct anything smaller? These are common questions asked by researchers, and the answers indicate the short-term limitations on the use of semiconductor technology. When we reach these limitations, we can propose two methods to solve these problems: first, we could continue using semiconductor technology, alongside the development of new theories and techniques to counter quantum effects caused by the miniaturization of electronic devices like transistors and microprocessors. Second, we could exploit these quantum effects to invent a new generation of electronic devices. Doing that, we propose spintronics or the use of spin properties. Heusler compounds as cobalt base alloys (Co 2 YZ) present particular interest for spin electronics applications. In this paper, we present properties and results for two cobalt base alloys, Co 2 FeGa and Co 2 FeSi. These properties are interesting for the field of quantum computation. In the first part of this paper we introduce Moore's law, which explains the major limits of semiconductor technology. Then we discuss the results of our calculations based on the use of density functional theory and the WIEN2K program. This is for the purpose of making new quantum devices.

show abstract

Structural defects analysis versus spin polarized tunneling in Co2FeAl/MgO/CoFe magnetic tunnel junctions with thick MgO barriers

Cited by 10 publications

References 27 publications

Enhanced magnetoresistance by monoatomic roughness in epitaxial Fe/MgO/Fe tunnel junctions

Enhanced magnetoresistance by monoatomic roughness in epitaxial Fe/MgO/Fe tunnel junctions

ELECTRONIC, STRUCTURAL AND MAGNETIC PROPERTIES OF Co₂FeAl THIN FILMS FOR POTENTIAL SPINTRONIC APPLICATIONS

Ab initio study of the structural, electronic, and magnetic properties of Co 2 FeGa and Co 2 FeSi and their future contribution to the building of quantum devices

Contact Info

Product

Resources

About

Structural defects analysis versus spin polarized tunneling in Co2FeAl/MgO/CoFe magnetic tunnel junctions with thick MgO barriers

Cited by 10 publications

References 27 publications

Enhanced magnetoresistance by monoatomic roughness in epitaxial Fe/MgO/Fe tunnel junctions

Enhanced magnetoresistance by monoatomic roughness in epitaxial Fe/MgO/Fe tunnel junctions

ELECTRONIC, STRUCTURAL AND MAGNETIC PROPERTIES OF Co2FeAl THIN FILMS FOR POTENTIAL SPINTRONIC APPLICATIONS

Ab initio study of the structural, electronic, and magnetic properties of Co 2 FeGa and Co 2 FeSi and their future contribution to the building of quantum devices

Contact Info

Product

Resources

About

ELECTRONIC, STRUCTURAL AND MAGNETIC PROPERTIES OF Co₂FeAl THIN FILMS FOR POTENTIAL SPINTRONIC APPLICATIONS