Strain Relaxation During Growth Of Epitaxial Fe on Cu(O01)/MgO(001)

1993 ◽  
Vol 312 ◽  
Author(s):  
B. J. Daniels ◽  
N. M. Rensing ◽  
J. A. Bain ◽  
S. Brennan ◽  
B. M. Lairson ◽  
...  

AbstractThe strain relaxation of sputter-deposited epitaxial Fe on Cu(001)/MgO(001) was observed in-situ for coverages of I to 200 equivalent monolayers of Fe. Grazing incidence x-ray scattering (GIXS) with synchrotron radiation allowed the precise determination of the in-plane strain in the Fe film. The highest observed elastic strain for the Fe was -10.3% which is in agreement with the lattice parameter mismatch between Fe and Cu for both (001)- and {211}-oriented growth. In-plane rocking curves revealed a bifurcation of the Fe(110) and Fe(220) peaks which is due to the rotation of islands to reduce strain energy. The angle of rotation of these islands was found to depend upon the amount of strain relaxation that had occurred in each island, in agreement with a simple theory for strain relaxation via the creation of a misfit dislocation network. The absence of Fe(200) intensity at small Fe thicknesses, coupled with out-of-plane symmetric and pole figure scans, suggest that Fe islands are tilted out of the plane of the sample about the Fe<110> axes by an angle consistent with Fe{211}-oriented growth. At larger thicknesses Fe(001) growth becomes dominant.

1994 ◽  
Vol 356 ◽  
Author(s):  
B. J. Daniels ◽  
W. D. Nix ◽  
B. M. Clemens

AbstractThe hardness of epitaxial sputter-deposited Fe(001)/Pt(001) multilayers grown on single crystal MgO(001) has been previously evaluated as a function of composition wavelength, Λ. Nanoindentation results reveal that the hardness is enhanced over that expected from a simple rule of mixtures by a factor of approximately 2.5 for bilayer spacings from 20 to 125 Å. In this paper we investigate possible causes of this hardness enhancement by determining the stress, strain, and alloying in each layer of the multilayer as a function of Λ. Accurate in-plane and out-of-plane lattice parameter measurements were obtained via x-ray diffraction using synchrotron radiation. The stress state and the extent of alloying in each layer as a function of Λ was determined by using the appropriate elastic constants for each component. The stress, strain, and amount of alloying in the Pt layer were near zero for 25≤Λ≤121 Å. The Fe layer exhibited large stresses and strains which relaxed with increasing Λ for 44≤Λ≤121 Å. For Λ=25 Å, the metastable FCC structure was adopted by the Fe film. The amount of alloying also varied from approximately 11 at.% Pt for Λ=44 Å to 5 at.% Pt for Λ=121 Å. Since the structure, film stress, amount of strain relaxation, and extent of alloying vary over this range of Λ while the hardness does not, we conclude that the hardness enhancement in these films must be controlled by other factors. Nevertheless the investigation of these basic film properties has enhanced our understanding of the structure-property relationships that give rise to strengthening in multilayer thin films.


1994 ◽  
Vol 356 ◽  
Author(s):  
S. G. Malhotra ◽  
Z. U. Rek ◽  
L. J. Parfitt ◽  
S. M. Yalisove ◽  
J. C. Bilello

AbstractTraditionally, the magnitude of the stress in a thin film is obtained by measuring the curvature of the film-substrate couple; however, these techniques all measure the average stress throughout the film thickness. On a microscopic level, the details of the strain distribution as a function of depth through the thickness of the film can have important consequences in governing film quality and ultimate morphology. A new method for determining the magnitude of principal strains (strain eigenvalues) as a function of x-ray penetration depth using grazing incidence x-ray scattering for a polycrystalline thin film will be described. Results are reported for two Mo metallizations ˜ 500 Å and ˜1000 Å thick sputtered onto Si {100} substrates. The magnitude of the principal strains at several penetration depths was accomplished by an analysis of the diffraction peak shifts of at least six independent {hkl} scattering vectors from the Mo thin films. An out-of-plane strain gradient was identified in both Mo films and the strain eigenvalues were found to be anisotropic in nature. This new methodology should work with a variety of thin films and hence would provide quantitative insight into the evolution of thin film microstructure.


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
O. A. Maslova ◽  
Yu. I. Yuzyuk ◽  
S. A. Barannikova

This work is aimed at studying asymmetric BaTiO31 − xΛ/BaZrO3xΛ ((BT) 1−xΛ/(BZ)xΛ) superlattices, grown by pulsed laser deposition onto (001) MgO substrates. The thicknesses of BT (ferroelectric) and BZ (paraelectric) layers were varied so that х ranged from 0 to 1 at a modulation period Λ of about 80 Å. The films were 400 nm thick. The out-of-plane lattice parameters of constituents were assessed using X-ray diffraction. The lattice dynamic peculiarities of superlattices were probed via Raman spectroscopy; special attention is paid to the analysis of E(1TO) and A1(2TO) ferroelectric soft modes. A comparative analysis of data acquired via both experimental techniques reveals the enhancement of stress between BT and BZ layers with a decrease in symmetry from the tetragonal to a monoclinic phase due to strains induced by the lattice parameter mismatch between the constituents.


1994 ◽  
Vol 340 ◽  
Author(s):  
G. Padeletti ◽  
G. M. Ingo ◽  
P. Imperatori

ABSTRACTGa0.65In0.35As layers of a varying nominal epilayer thickness (10 – 1000 nm) have been grown by the MBE technique on GaAs (100) substrates and characterized by the combined use of atomic force microscopy (AFM) and grazing incidence X-ray diffraction (GIXD). The surface roughness and morphology have been investigated. The GIXD and AFM results show that the thinnest films are characterized by an asymmetric strain relaxation along the two <110> directions with no surface crosshatched pattern but with a misfit dislocation network. AFM images on the thickest films show also well-oriented protrusions along the [110] direction, which increase in size and become more elongated as the nominal film thickness increases.


2005 ◽  
Vol 19 (15n17) ◽  
pp. 2415-2420 ◽  
Author(s):  
W. S. TAN ◽  
Q. J. JIA ◽  
J. GAO

La 0.7 Ca 0.3 MnO 3(LCMO) thin films with the thickness of 50 nm were deposited on (001)-oriented single crystal SrTiO 3(STO), MgO and α- Al 2 O 3(ALO) by 90° off-axis radio frequency magnetron sputtering. Grazing incidence X-ray diffraction technique, associated with normal X-ray diffraction, was performed to measure the in-plane lattice parameter and investigate the lattice strain and strain relaxation in LCMO films. The results indicated that critical thickness of strain relaxation is very small, which may be related to large mismatch between film and substrate. The mechanism for strain relaxation in LCMO film is perhaps different from that for tetragonal distortion.


1993 ◽  
Vol 308 ◽  
Author(s):  
Paul R. Besser ◽  
Thomas N. Marieb ◽  
John C. Bravman

ABSTRACTStrain relaxation in passivated Al-0.5% Cu lines was measured using X-ray diffraction coupled with in-situ observation of the formation and growth of stress induced voids. Samples of 1 μm thick Al-0.5% Cu lines passivated with Si3N4 were heated to 380ºC, then cooled and held at 150ºC. During the test, principal strains along the length, width, and height of the line were determined using a grazing incidence x-ray geometry. From these measurements the hydrostatic strain in the metal was calculated and strain relaxation was observed. The thermal cycle was duplicated in a high voltage scanning transmission electron microscope equipped with a backscattered electron detector. The 1.25 μm wide lines were seen to have initial stress voids. Upon heating these voids reduced in size until no longer observable. Once the samples were cooled to 150ºC, voids reappeared and grew. The measured strain relaxation is discussed in terms of void and θ-phase (Al2Cu) formation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Snehashish Tripathy ◽  
Sandip Ghosh Chowdhury

AbstractA novel directional inoculation technique has been designed to cast thin slab ingots containing Goss (or near Goss) oriented components in the as cast microstructure under the combined effect of oriented nucleation and oriented growth. The same has been targeted so as to retain Goss orientations and simultaneously develop γ fiber components (ranging from {111}<$$1\overline{1}0$$ 1 1 ¯ 0 > to {111}<112>) during hot rolling. The designed scheme of directional inoculation achieved oriented nucleation by the effect of exogenously added soft magnetic inoculants under magnetic field and oriented growth by the effect of fast cooling rates prevailing in the mould. The choice of 65Fe–35Co (wt%) system as soft magnetic inoculants was made taking into account the similarity in crystal structure and lattice parameter. The chemically synthesized inoculants under the effect of external magnetic field during solidification were able to exhibit directional inoculation. Variation in the cast microstructure and microtexture by varying the extent of inoculant addition was studied by EBSD technique. The ingots cast under different conditions were subjected to a designed hot rolling schedule and the through process microstructural and microtextural evolution was assessed. It was observed that fine equiaxed grains with initial cube orientations in the as cast structure could lead to the most desirable microstructural as well as microtextural gradient in the hot band.


1997 ◽  
Vol 292 (1-2) ◽  
pp. 277-281 ◽  
Author(s):  
D.K. Aswal ◽  
S.K. Gupta ◽  
Savita N. Narang ◽  
S.C. Sabharwal ◽  
M.K. Gupta

1999 ◽  
Vol 14 (7) ◽  
pp. 2905-2911 ◽  
Author(s):  
Sangsub Kim ◽  
Tae Soo Kang ◽  
Jung Ho Je

Epitaxial (Ba0.5Sr0.5) TiO3 thin films of two different thickness (∼25 and ∼134 nm) on MgO(001) prepared by a pulsed laser deposition method were studied by synchrotron x-ray scattering measurements. The film grew initially with a cube-on-cube relationship, maintaining it during further growth. As the film grew, the surface of the film became significantly rougher, but the interface between the film and the substrate did not. In the early stage of growth, the film was highly strained in a tetragonal structure (c/a = 1.04) with the longer axis parallel to the surface normal direction. As the growth proceeded further, it relaxed to a cubic structure with the lattice parameter near the bulk value, and the mosaic distribution improved significantly in both in- and out-of-plane directions. The thinner film (∼25 nm) showed only one domain limited mainly by the film thickness, but the thicker film (∼134 nm) exhibited three domains along the surface normal direction.


2013 ◽  
Vol 46 (4) ◽  
pp. 887-892 ◽  
Author(s):  
Genziana Bussone ◽  
Rüdiger Schott ◽  
Andreas Biermanns ◽  
Anton Davydok ◽  
Dirk Reuter ◽  
...  

Grazing-incidence X-ray diffraction measurements on single GaAs nanowires (NWs) grown on a (111)-oriented GaAs substrate by molecular beam epitaxy are reported. The positions of the NWs are intentionally determined by a direct implantation of Au with focused ion beams. This controlled arrangement in combination with a nanofocused X-ray beam allows the in-plane lattice parameter of single NWs to be probed, which is not possible for randomly grown NWs. Reciprocal space maps were collected at different heights along the NW to investigate the crystal structure. Simultaneously, substrate areas with different distances from the Au-implantation spots below the NWs were probed. Around the NWs, the data revealed a 0.4% decrease in the lattice spacing in the substrate compared with the expected unstrained value. This suggests the presence of a compressed region due to Au implantation.


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