Etude de la mise en ordre de l'alliage pt-co equiatomique par microscopie electronique

Pénisson, J.M.; Bourret, A.; Eurin, P.

doi:10.1016/0001-6160(71)90052-6

Cited by 48 publications

(4 citation statements)

References 12 publications

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“…It is well recognized that the tweed microstructure is frequently observed as a microstructural aspects of pre-martensitic phenomena 8) or the initial stage of disorder-order transformation from a cubic to tetragonal phase. 9,10) The reason for formation of the tweed microstructure is attributed to the local tetragonal distortion in the cubic structure. Table 1.…”

Section: Resultsmentioning

confidence: 99%

Electron Microscopy Study of Preferential Variant Selection in CoPt Alloy Ordered under a Magnetic Field

et al. 2013

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Transmission electron microscope (TEM) and scanning transmission electron microscope (STEM) observations were carried out to investigate microstructure formation and variant selection process in L1 0 -type ordered CoPt alloy upon a two-step ordering heat-treatment. The first step corresponds to nucleation process carried out under a magnetic field of 10 T and the second step represents growth process without magnetic field. After the first step of ordering, ordered domains of about 5 nm in size were observed and fraction of the preferred variant with the c-axis parallel to applied magnetic field was slightly higher than that of the other two variants. Formation of tweed microstructure along f011g L10 was confirmed at the initial stage of ordering. This structure is considered to be derived from the periodic alignment of interface between two ordered variants with twin relation. At the early stage of the second step of ordering, numerous micro-twins were formed through tweed microstructure and the volume fraction of the preferred variant was increased accompanying with modulation of twins, while that of other two variants was decreased. After the second step of ordering, the twins were vanished and single variant was obtained.

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Section: Resultsmentioning

confidence: 99%

Electron Microscopy Study of Preferential Variant Selection in CoPt Alloy Ordered under a Magnetic Field

et al. 2013

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“…The magnetic alloy CoPt, when grown on ͑100͒ MgO at ഛ600°C, has a disordered fcc structure with a lattice parameter of 3.772 Å. 26 The lattice mismatch for epitaxial growth of A on B can be characterized in terms of the strain parameter ⑀ defined as ⑀ = It is interesting to note that in spite of a large strain parameter ͑⑀ Ϸ −16.4% ͒, CoPt prefers to grow epitaxially with a slight change ͑Ϸ0.2% ͒ in lattice parameter from bulk when deposited on NbN ͓Fig. 2͑b͔͒.…”

Section: A Bilayers With In-plane Magnetic Anisotropymentioning

confidence: 99%

Lattice-mismatch-induced granularity in CoPt-NbN and NbN-CoPt superconductor-ferromagnet heterostructures: Effect of strain

et al. 2008

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The effect of strain due to lattice mismatch and of ferromagnetic exchange field on superconductivity ͑SC͒ in NbN-CoPt bilayers is investigated. Two different bilayer systems with reversed deposition sequence are grown on MgO ͑001͒ single crystals. While robust superconductivity with high critical temperature ͑T c Ϸ 15.3 K͒ and narrow transition width ͑⌬T c Ϸ 0.4 K͒ is seen in two types of CoPt-NbN / MgO heterostructures where the magnetic anisotropy of CoPt is in plane in one case and out of plane in the other, the NbN-CoPt/ MgO system shows markedly suppressed SC response. The reduced SC order parameter of this system, which manifests itself in T c , temperature dependence of critical current density J c ͑T͒, and angular ͑͒ variation of flux-flow resistivity f , is shown to be a signature of the structure of NbN film and not a result of the exchange field of CoPt. The f ͑H , T , ͒ data further suggest that the domain walls in the CoPt film are of the Néel type and hence do not cause any flux in the superconducting layer. A small but distinct increase in the low-field critical current of the CoPt-NbN couple is seen when the magnetic layer has perpendicular anisotropy.

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“…Antiphase boundaries (APBs) are observed in both types of domains, as thin anisotropic dark lines 13,15,20,21 that correspond to chemically disordered volumes. Furthermore, an interfacial layer of about 8 nm is observed on both types of dark field images at the FePd/ Pd interface.…”

Section: Transmission Electron Microscopy (Tem) and Electron Enermentioning

confidence: 99%

Chemical ordering in magneticFePd∕Pd(001)epitaxial thin films induced by annealing

et al. 2004

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Chemically disordered FePd epitaxial layers are grown at room temperature by molecular beam epitaxy on a Pd(001) buffer layer and then annealed in order to induce the chemically ordered L1 0 (AuCu I) structure. Contrary to what is observed in the case of ordering during growth above room temperature, the ordered structure appears here with the three possible variants of the L1 0 phase. The ratio of the three different variant volumes is set by the residual epitaxial strain in the layer before annealing. It thus explains that for long annealing times, the long-range order parameter associated with the L1 0 variant with c along the (100) growth direction saturates at a value close to 0.65, and never reaches unity. Magnetic consequences of the ordering are studied.

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Etude de la mise en ordre de l'alliage pt-co equiatomique par microscopie electronique

Cited by 48 publications

References 12 publications

Electron Microscopy Study of Preferential Variant Selection in CoPt Alloy Ordered under a Magnetic Field

Electron Microscopy Study of Preferential Variant Selection in CoPt Alloy Ordered under a Magnetic Field

Lattice-mismatch-induced granularity in CoPt-NbN and NbN-CoPt superconductor-ferromagnet heterostructures: Effect of strain

Chemical ordering in magneticFePd∕Pd(001)epitaxial thin films induced by annealing

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