Epitaxy

Ohring, Milton

doi:10.1016/b978-012524975-1/50011-2

Cited by 45 publications

(60 citation statements)

References 49 publications

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“…The Poisson ratio was calculated from the experimental LSMO cell parameters of the fully strained 2.0 nm film measured by high-resolution XRD 2θ/ω scans (out-of-plane c = 3.985 Å; in-plane a = 3.790 Å). Assuming an equilibrium cell structure a = 3.885 Å, the corresponding strains are ε // = −0.0244; ε ⊥ = +0.0257, and the Poisson ratio calculated from the expression for biaxial strain ε ∥ = −(2 v /1 – v )ε ⊥ was ν = 0.32. Therefore, a critical thickness of h c = 1.7 nm is obtained from eq , which is slightly below the experimental observation.…”

Section: Resultsmentioning

confidence: 99%

Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La_0.7Sr_0.3MnO₃/LaAlO₃(100) Epitaxial Films under Compressive Strain

Santiso

Roqueta

Bagués

et al. 2016

ACS Appl. Mater. Interfaces

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Lattice-mismatched epitaxial films of La0.7Sr0.3MnO3 (LSMO) on LaAlO3 (001) substrates develop a crossed pattern of misfit dislocations above a critical thickness of 2.5 nm. Upon film thickness increases, the dislocation density progressively increases, and the dislocation spacing distribution becomes narrower. At a film thickness of 7.0 nm, the misfit dislocation density is close to the saturation for full relaxation. The misfit dislocation arrangement produces a 2D lateral periodic structure modulation (Λ ≈ 16 nm) alternating two differentiated phases: one phase fully coherent with the substrate and a fully relaxed phase. This modulation is confined to the interface region between film and substrate. This phase separation is clearly identified by X-ray diffraction and further proven in the macroscopic resistivity measurements as a combination of two transition temperatures (with low and high Tc). Films thicker than 7.0 nm show progressive relaxation, and their macroscopic resistivity becomes similar than that of the bulk material. Therefore, this study identifies the growth conditions and thickness ranges that facilitate the formation of laterally modulated nanocomposites with functional properties notably different from those of fully coherent or fully relaxed material.

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Section: Resultsmentioning

confidence: 99%

Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La_0.7Sr_0.3MnO₃/LaAlO₃(100) Epitaxial Films under Compressive Strain

Santiso

Roqueta

Bagués

et al. 2016

ACS Appl. Mater. Interfaces

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“…The dominant growth mechanism for FePt films grown on MgO substrates is 3D island (Volmer-Weber) growth mode considering their surface energy ( γ FePT ~ 2 J m −2 , γ MgO ~ 1.1–1.2 J m −2 ) and large lattice mismatch (~9.6%). In this growth mode, the film becomes continuous only at or above a critical thickness that is influenced by the surface energy and lattice mismatch differences as well as the substrate temperature during deposition 7 . Although a 50–100 nm thickness range has been reported to be a critical thickness for FePt films on (100) MgO deposited at ~973 K 8 , our results show that the thickness of ~100 nm is not sufficient to form a 100% continuous layer with no surface pores for FePt deposition on MgO at 1,023 K.…”

Section: Resultsmentioning

confidence: 99%

Influence of chemical ordering on the thermal conductivity and electronic relaxation in FePt thin films in heat assisted magnetic recording applications

Giri

Wee

Jain

et al. 2016

Sci Rep

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We report on the out-of-plane thermal conductivities of tetragonal L10 FePt (001) easy-axis and cubic A1 FePt thin films via time-domain thermoreflectance over a temperature range from 133 K to 500 K. The out-of-plane thermal conductivity of the chemically ordered L10 phase with alternating Fe and Pt layers is ~23% greater than the thermal conductivity of the disordered A1 phase at room temperature and below. However, as temperature is increased above room temperature, the thermal conductivities of the two phases begin to converge. Molecular dynamics simulations on model FePt structures support our experimental findings and help shed more light into the relative vibrational thermal transport properties of the L10 and A1 phases. Furthermore, unlike the varying temperature trends in the thermal conductivities of the two phases, the electronic scattering rates in the out-of-plane direction of the two phases are similar for the temperature range studied in this work.

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“…It is noted that to minimize deviation from the stoichiometry of CaBi 2 Nb 2 O 9 , we chose a moderate sputtering power and an optimal sputtering atmosphere with an Ar/O 2 flow ratio of 4:1. While the former limits the bulk diffusion of the target and hence help maintain its self-compensating mechanism of stoichiometry in a preferential sputtering process, the latter has been proven to yield sputtered peroskite films with both a dense microstructure and a good chemical stoichiometry. , …”

Section: Experimental Sectionmentioning

confidence: 99%

Strain Engineered CaBi₂Nb₂O₉ Thin Films with Enhanced Electrical Properties

Zhang

Ouyang

Zhang

et al. 2016

ACS Appl. Mater. Interfaces

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In this work, strain engineered polycrystalline thin films (∼250 nm) of bismuth layer-structured ferroelectric (BLSF) CaBi2Nb2O9 (CBNO) were prepared by using a radio frequency (RF) magnetron sputtering technique. XRD analysis revealed that the films were (200)/(020) and (00l) textured with a large in-plane tensile stress. Cross-sectional TEM analyses confirmed the bismuth layered-structure, as well as crystalline orientations and a strain-controlled growth mode of the grains. Result of a quantitative XPS analysis revealed that the composition of the film is close to the chemical stoichiometry. Excellent electrical properties were achieved in the CBNO films, including a high dielectric constant (∼280 @5 kHz), a small dielectric loss (tgδ ≤ 1.6% up to an applied electric field of ∼1200 kV/cm) and a large polarization (Pr ≈ 14 μC/cm(2) @ 1 kHz).

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Epitaxy

Cited by 45 publications

References 49 publications

Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La_0.7Sr_0.3MnO₃/LaAlO₃(100) Epitaxial Films under Compressive Strain

Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La_0.7Sr_0.3MnO₃/LaAlO₃(100) Epitaxial Films under Compressive Strain

Influence of chemical ordering on the thermal conductivity and electronic relaxation in FePt thin films in heat assisted magnetic recording applications

Strain Engineered CaBi₂Nb₂O₉ Thin Films with Enhanced Electrical Properties

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Epitaxy

Cited by 45 publications

References 49 publications

Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La0.7Sr0.3MnO3/LaAlO3(100) Epitaxial Films under Compressive Strain

Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La0.7Sr0.3MnO3/LaAlO3(100) Epitaxial Films under Compressive Strain

Influence of chemical ordering on the thermal conductivity and electronic relaxation in FePt thin films in heat assisted magnetic recording applications

Strain Engineered CaBi2Nb2O9 Thin Films with Enhanced Electrical Properties

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Product

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Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La_0.7Sr_0.3MnO₃/LaAlO₃(100) Epitaxial Films under Compressive Strain

Self-Arranged Misfit Dislocation Network Formation upon Strain Release in La_0.7Sr_0.3MnO₃/LaAlO₃(100) Epitaxial Films under Compressive Strain

Strain Engineered CaBi₂Nb₂O₉ Thin Films with Enhanced Electrical Properties