Compositional dependence of the magnetic properties of epitaxial FeV/MgO thin films

Devolder, T.; Tahmasebi, T.; Eimer, Sylvain; Hauet, Thomas; Andrieu, S.

doi:10.1063/1.4845375

Cited by 32 publications

(19 citation statements)

References 34 publications

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“…This splitting is indicative of an exchange stiffness of A ¼ 13 6 1 pJ/m. 14 The low damping value is consistent with typical HMM behavior for which the damping coefficient is expected to be very small due to the lack of minority spin DOS at the Fermi level. All these results are strong indications that chemical disorder is very limited in our films.…”

Section: A)supporting

confidence: 80%

Testing epitaxial Co1.5Fe1.5Ge(001) electrodes in MgO-based magnetic tunnel junctions

Neggache

Hauet

Bertran

et al. 2014

Applied Physics Letters

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The ability of the full Heusler alloy Co1.5Fe1.5Ge(001) (CFG) to be a Half-Metallic Magnetic (HMM) material is investigated. Epitaxial CFG(001) layers were grown by molecular beam epitaxy. The results obtained using electron diffraction, X-ray diffraction, and X-ray magnetic circular dichroism are consistent with the full Heusler structure. The pseudo-gap in the minority spin density of state typical in HMM is examined using spin-resolved photoemission. Interestingly, the spin polarization found to be negative at EF in equimolar CoFe(001) is observed to shift to positive values when inserting Ge in CoFe. However, no pseudo-gap is found at the Fermi level, even if moderate magnetization and low Gilbert damping are observed as expected in HMM materials. Magneto-transport properties in MgO-based magnetic tunnel junctions using CFG electrodes are investigated via spin and symmetry resolved photoemission.

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Section: A)supporting

confidence: 80%

Testing epitaxial Co1.5Fe1.5Ge(001) electrodes in MgO-based magnetic tunnel junctions

Neggache

Hauet

Bertran

et al. 2014

Applied Physics Letters

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“…Indeed, the direct evidence of a spin gap in the minority spin channel was reported only very recently in Co 2 MnSi [28,29]. On the other hand, as small magnetic damping coefficients were reported for several Heusler compounds, the measured values still remained in the 10 -3 range [30][31][32][33][34][35] which is at least 10 times larger than prediction and comparable with epitaxial FeV alloys [19] which are not HMM. In 2016, we measured for the first time a damping coefficient in the 10 -4 range [29] (7.10 -4 in Co 2 MnSi, which was confirmed by another group in 2018 [36]).…”

Section: -Introductionmentioning

confidence: 71%

Ultralow Magnetic Damping in Co2Mn -Based Heusler Compounds: Promising Materials for Spintronics

et al. 2019

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The prediction of ultra-low magnetic damping in Co 2 MnZ Heusler half-metal thin-film magnets is explored in this study and the damping response is shown to be linked to the underlying electronic properties. By substituting the Z elements in high crystalline quality films (Co 2 MnZ with Z=Si, Ge, Sn, Al, Ga, Sb), electronic properties such as the minority spin band gap, Fermi energy position in the gap and spin polarization can be tuned and the consequence on magnetization dynamics analyzed. The experimental results allow us to directly explore the interplay of spin polarization, spin gap, Fermi energy position and the magnetic damping obtained in these films, together with ab initio calculation predictions. The ultra-low magnetic damping coefficients measured in the range 4.1 10 -4 -9 10 -4 for Co 2 MnSi, Ge, Sn, Sb are the lowest values obtained on a conductive layer and offers a clear experimental demonstration of theoretical predictions on Half-Metal Magnetic Heusler compounds and a pathway for future materials design.

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“…These transitions do not exist in HMM, such that their damping should be comparable to that of insulators, i.e. lower than that of Fe (alpha=0.0019), which is the lowest damping among metallic magnets [Dev13]. We thus measured the dynamic magnetic properties of Au covered CMS samples using Vector Network Analyzer FerroMagnetic Resonance (VNAFMR) [Bil08] in both inplane and out-of-plane applied fields.…”

Section: Figure 4:influence Of Mn and Mgo Coverage On Cms Electronic mentioning

confidence: 99%

Direct evidence for minority spin gap in theCo2MnSiHeusler compound

et al. 2016

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Half Metal Magnets are of great interest in the field of spintronics because of their potential full spin-polarization at the Fermi level and low magnetization damping. The high Curie temperature and predicted 0.7eV minority spin gap make the Heusler alloy Co 2 MnSi very promising for applications.We investigated the half-metallic magnetic character of this alloy using spin-resolved photoemission, ab initio calculation and ferromagnetic resonance. At the surface of Co 2 MnSi, a gap in the minority spin channel is observed, leading to 100%spin polarization. However, this gap is 0.3 eV below the Fermi level and a minority spin state is observed at the Fermi level. We showthat a minority spin gap at the Fermi energy can neverthelessbe recovered either by changing the stoichiometry of the alloy or by covering the surface byMn, MnSi or MgO. This results in extremely small damping coefficients reachingvalues as low as7x 10 -4 .

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Compositional dependence of the magnetic properties of epitaxial FeV/MgO thin films

Cited by 32 publications

References 34 publications

Testing epitaxial Co1.5Fe1.5Ge(001) electrodes in MgO-based magnetic tunnel junctions

Testing epitaxial Co1.5Fe1.5Ge(001) electrodes in MgO-based magnetic tunnel junctions

Ultralow Magnetic Damping in Co2Mn -Based Heusler Compounds: Promising Materials for Spintronics

Direct evidence for minority spin gap in theCo2MnSiHeusler compound

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