Magnetic interactions involving ferromagnetic layers separated by an insulating barrier have been studied experimentally on a fully epitaxial hard-soft magnetic tunnel junction: Fe/MgO/Fe/Co. For thickness below 1 nm, clear antiferromagnetic interaction is observed. Moreover, when reducing the MgO from to 0.5 coupling strength increases up J=-0.26 erg.cm(-2). This behavior, well fitted theoretical models, provides unambiguous signature of interlayer exchange spin-polarized quantum tunneling.

Co2FeAl (CFA) thin films with thickness varying from 10 nm to 115 have been deposited on MgO(001) substrates by magnetron sputtering and then capped Ta or Cr layer. X-rays diffraction (XRD) revealed that the cubic $[001]$ CFA axis is normal substrate all exhibit full epitaxial growth. The chemical order varies $B2$ phase $A2$ when decreasing thickness. Magneto-optical Kerr effect (MOKE) vibrating sample magnetometer measurements show that, depending field orientation, one two-step switchings...

Brillouin light scattering (BLS), complemented by ferromagnetic resonance (FMR) characterization, has been used for studying spin-wave (SW) propagation in $\mathrm{Py}(L)/\mathrm{Pt}(6\text{\ensuremath{-}}\mathrm{nm})$ bilayers of various Py thicknesses $(4\phantom{\rule{0.16em}{0ex}}\mathrm{nm}\ensuremath{\le}L\ensuremath{\le}10\phantom{\rule{0.16em}{0ex}}\mathrm{nm})$. The FMR measurements allowed determination the pertinent magnetic parameters and revealed existence a normal surface...

We report on spin-polarized tunneling in fully epitaxial Fe/MgO/Fe/Co tunnel junctions. By increasing the thickness of insulating layer (tMgO), we have strongly enhanced magnetoresistance. Values up to ∼100% at 80 K (∼67% room temperature) been observed with tMgO=2.5 nm. This magnetoresistance ratio, which is much larger than one predicted by Jullière’s model, can be understood framework ab initio calculations.

The direct impact of the electronic structure on spin-polarized transport has been experimentally proven in high-quality $\mathrm{F}\mathrm{e}/\mathrm{M}\mathrm{g}\mathrm{O}/\mathrm{F}\mathrm{e}$ epitaxial magnetic tunnel junctions, with an extremely flat bottom $\mathrm{F}\mathrm{e}/\mathrm{M}\mathrm{g}\mathrm{O}$ interface. voltage variation conductance points out signature interfacial resonance state located minority band Fe(001). When coupled to a metallic bulk state, this enhances...

This paper shows the correlation between chemical order, lattice strains and magnetic properties of Heusler Co2FeAl films epitaxially grown on MgO(001). A detailed characterization has been performed using vector field magnetometery combined with numerical Stoner-Wohlfarth analysis. We demonstrate presence three types in-plane anisotropies: one biaxial, as expected for cubic symmetry, other two uniaxial ones. The anisotropies show different behavior annealing temperature. biaxial anisotropy...

A brief theoretical review points out the specific aspects of electronic transport in single-crystal magnetic tunnel junctions employing bcc(100) Fe electrodes and a MgO(100) insulating barrier. The predictions are compared to experimental reality both equilibrium out-of-equilibrium regimes. For extremely small MgO thickness, we illustrate that Fe/MgO/Fe systems leads antiferromagnetic interactions. Artificial based on coupling by spin polarized tunnelling have been elaborated studied. In...

10 nm and 50 Co2FeAl (CFA) thin films have been deposited on MgO(001) Si(001) substrates by magnetron sputtering annealed at different temperatures. X-rays diffraction revealed polycrystalline or epitaxial growth (according to CFA(001)[110]//MgO(001)[100] relation) for CFA grown a Si MgO substrate, respectively. For these later, the chemical order varies from A2 phase B2 when increasing annealing temperature (Ta), while only disorder type has observed Si. Microstrip ferromagnetic resonance...

$\mathrm{C}{\mathrm{o}}_{0.5}\mathrm{F}{\mathrm{e}}_{0.5}$ (CoFe) ultrathin films of various thicknesses $(0.8\phantom{\rule{0.16em}{0ex}}\mathrm{nm}\ensuremath{\le}{t}_{\mathrm{CoFe}}\ensuremath{\le}1.6\phantom{\rule{0.16em}{0ex}}\mathrm{nm})$ have been grown by sputtering on (001) MgO single crystal or Si/${\mathrm{SiO}}_{2}$ substrates, using Pt as capping buffer layers, respectively. The x-ray diffraction revealed an in-plane epitaxial (isotropic) growth (Si). Their magnetic properties...

Spin-orbit coupling (SOC) is a key interaction in spintronics, allowing electrical control of spin or magnetization and, vice versa, magnetic current. However, recent advances have revealed much broader implications SOC that also central to the design topological states with potential applications from low-energy dissipation and faster switching high tolerance disorder. resulting emergent interfacial spin-orbit fields are simply realized junctions through structural inversion asymmetry,...

We report in this paper on the study and realization of surface acoustic wave devices based an AlN/diamond layered structure intended for X band (8 GHz). Both x-ray diffraction transmission electronic microscopy, used characterization structural properties structure, have shown (002) highly oriented sputtered AlN films free-standing chemical vapor deposition diamond films. Surface roughness was measured by atomic force microscopy showed a very low roughness, less than 1 nm. Low is important...

We report on the experimental observation of tunneling across an ultrathin metallic Cr spacer layer that is inserted at interface a Fe/MgO/Fe(001) junction. show how this remarkable behavior in solid-state device reflects quenching transmission particular electronic states, as expected from symmetry-filtering properties MgO barrier and band structure bcc Cr(001) epitaxial junction stack. This can promote quantum well states adjacent Fe layer.

Piezoelectric aluminum nitride films were deposited onto 3 in. [0001] sapphire substrates by reactive magnetron sputtering to explore the possibility of making highly (002)-textured AlN be used in surface acoustic wave (SAW) devices for high temperature applications. The synthesized films, typically 1 μm thick, exhibited a columnar microstructure and c-axis texture. relationship between microstructures process conditions was examined x-ray diffraction (XRD), transmission electron microscopy,...

Bending effect on the magnetic anisotropy in 20 nm Co2FeAl Heusler thin film grown Kapton® has been studied by ferromagnetic resonance and glued curved sample carrier with various radii. The results reported this Letter show that is drastically changed system bending films. This attributed to interfacial strain transmission from substrate magnetoelastic behavior of film. Moreover, two approaches determine in-plane magnetostriction coefficient film, leading a value close λCFA = 14 × 10−6,...

The structural and chemical order are the most important parameters governing physical properties of Heusler compounds. Here, we give a comprehensive overview correlations between order, electronic transport (longitudinal transverse) magnetic (static dynamic) ${\mathrm{Co}}_{2}{\mathrm{FeAl}}_{0.5}{\mathrm{Si}}_{0.5}$ alloy epitaxial thin films grown on MgO(001) single-crystal substrates. X-ray diffraction measurements indicated that depending annealing temperature show $B2$ or $L{2}_{1}$...

Local transport properties of Al2O3 tunnel barriers have been investigated at a nanometric spatial scale with an unconventional near field microscope. Using the tunneling effect, which is extremely sensitive to fluctuations barrier parameters (less than 1 2 A), unique method introduced investigate quality. This technique provides atomic information on characteristics cannot be obtained by conventional surface analysis techniques since they are all subject averaging over and depth.

Magnetotransport in epitaxial magnetic tunnel junctions is investigated while varying the density of dislocations MgO barrier. Fe-V alloys with variable composition and lattice mismatch are used as electrodes. The reduction dislocation was probed by reflection high-energy electron diffraction high-resolution microscopy. Spin-resolved photoemission together first-principles calculations were to study $\ensuremath{\Delta}$ bands alloys. Although their polarization decreases upon alloying,...

We report on a thorough experimental investigation of the influence an FeO layer at Fe/MgO interface magnetotransport properties in epitaxial Fe/MgO/Fe(001) magnetic tunnel junctions. Interfacial oxygen is introduced by adsorbing ${\text{O}}_{2}$ bottom Fe(001) layer. The morphology and composition film are investigated means scanning tunneling microscopy, reflection high-energy electron diffraction, x-ray photoelectrons spectroscopy. show that amount interfacial can be precisely tuned...

In this paper, we demonstrate the stabilization of perpendicular magnetic anisotropy (PMA) in Ta/Co2FeAl/MgO multilayers sputtered on thermally oxidized Si(100) substrates. The analysis points out that these films show significant interfacial even as-deposited state, KS=0.67 erg/cm2, enough to provide PMA for with thicknesses below 1.5 nm. Moreover, is enhanced by thermal annealing up 300 °C. presence a dead layer, whose thickness increases temperature, was also identified.

Magnetization switching by current induced spin–orbit torques (SOTs) in heavy metal/ferromagnetic metal/oxide structures is of great research interest due to its potential applications the field low power consumption spintronic devices. Here, we study Slonczewski-like and field-like SOT effective fields β-W/Co2FeAl/MgO showing perpendicular magnetic anisotropy (PMA). We characterize using harmonic Hall voltage measurements point out essential role planar effect corrections. estimate that for...

The interaction between superconductivity and ferromagnetism in thin film superconductor/ferromagnet heterostructures is usually reflected by a change of the S layer set magnetic state F layers. Here we report converse effect: transformation magnetocrystalline anisotropy single Fe(001) layer, thus its preferred magnetization orientation, driven an underlying V through spin-orbit coupled MgO interface. We attribute this to additional contribution free energy ferromagnet arising from...

Epitaxially grown magnetic tunnel junctions MgO(100)/Fe/MgO/Fe/Co/Pd have been elaborated by molecular beam epitaxy, with insulating layer thickness down to 0.8 nm. The continuity of this was checked at different spatial scales means morphological (high resolution transmission electronic microscopy), electric (local impedance), and (magnetoresistance hysteresis loop) measurements. These show a low resistance (4 kΩ μm2), magnetoresistance up 17%, very small interlayer coupling.

Low temperature (10K) high voltage bias dynamic conductivity (up to 2.7V) and shot noise 1V) were studied in epitaxial Fe(100)∕Fe–C∕MgO(100)∕Fe(100) magnetic tunnel junctions as a function of the state. The show large magnetoresistance (185% at 300K 330% 4K). Multiple sign inversion is observed for polarity when electrons scan electronic structure bottom Fe–C interface. shows Poissonian character. This demonstrates pure spin-dependent direct tunneling mechanism validates structural quality...

Fully epitaxial Fe(001)∕Fe3O4(001)∕MgO(001)∕Co micron-sized magnetic tunnel junctions have been elaborated on MgO(001) substrates. X-ray reflectivity and high-resolution transmission electron microscopy revealed a good quality growth of the stack with abrupt interfaces. The magnetotransport measurements exhibit large negative tunneling magnetoresistance (TMR) value for including an Fe3O4 layer MgO barrier (−8.5% at 300K −22% 80K). Moreover, sign TMR changes applied bias. We discuss here...

We demonstrate tunable ferrimagnetic properties in both bulk and thin film DyCo3 compatible with the hosting of topological magnetic chiral textures, namely skyrmions suitable for integration into spintronic applications classic, neuromorphic quantum functionalities. The samples were prepared by arc-melting stoichiometric mixtures under purified argon atmosphere films Ultra-High-Vacuum magnetron sputtering from a target. Magnetometry allows us to extract main films: saturation magnetization,...