Y1Ba2Cu3O7−<i>x</i> thin films grown on sapphire with epitaxial MgO buffer layers

Berezin, A. B.; Yuan, Chunhao; Lozanne, Alex de

doi:10.1063/1.104238

Cited by 93 publications

(22 citation statements)

References 10 publications

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“…Since it is a prototypical ionic insulator with a wide band gap, motivation is high to grow MgO films on a conductive substrate useful for charged-particle measurement, in addition to the applications mentioned above. Moreover, the usefulness of MgO films as buffer layers for the growth of high T c superconducting [5], and ferroelectric [6,7] films has led to an increased interest in the growth of this material. The most important point in these applications is the preparations of highly (100) oriented MgO thin films that can prevent inter-diffusion between the superconducting films and substrate and solve chemical reactivity at higher temperatures [8].…”

Section: Introductionmentioning

confidence: 99%

Spray pyrolysis deposition and characterization of highly (100) oriented magnesium oxide thin films

Raj¹,

Nehru

Jayachandran

et al. 2007

Cryst. Res. Technol.

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Transparent dielectric thin films of MgO has been deposited on quartz substrates at different temperatures between 400 and 600°C by a pneumatic spray pyrolysis technique using Mg(CH 3 COO) 2 .4H 2 O as a single molecular precursor. The thermal behavior of the precursor magnesium acetate is described in the results of thermogravimetry analysis (TGA) and differential thermal analysis (DTA). The prepared films are reproducible, adherent to the substrate, pinhole free and uniform. Amongst the different spray process parameters, the substrate temperature effect has been optimized for obtaining single crystalline and transparent MgO thin films. The films crystallize in a cubic structure and X-ray diffraction measurements have shown that the polycrystalline MgO films prepared at 500°C with (100) and (110) orientations are changed to (100) preferred orientation at 600°C. The MgO phase formation was also confirmed with the recorded Fourier Transform Infrared (FTIR) results. The films deposited at 600°C exhibited highest optical transmittivity (>80%) and the direct band gap energy was found to vary from 4.50 to 5.25 eV with a rise in substrate temperature from 500 to 600°C. The measured sheet resistance and the resistivity of the film prepared at 600°C were respectively 10 13 Ω/□ and 2.06x107 Ω cm. The surface morphology of the prepared MgO thin films was examined by atomic force microscopy.

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Section: Introductionmentioning

confidence: 99%

Spray pyrolysis deposition and characterization of highly (100) oriented magnesium oxide thin films

Raj¹,

Nehru

Jayachandran

et al. 2007

Cryst. Res. Technol.

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“…x. The exact value for the critical angle of total reflection 0, can be used to determine the mass density p of a deposited film14 @,=A (7) and where N , is the Avogadro constant, ro is the classical electron radius, ( Z +f') is the atomic scattering factor, and A is the atomic weight.…”

Section: F(l) = As(l)fd(l)mentioning

confidence: 99%

Characterization of MgO layers on different alumina and glass substrates by grazing incidence diffractometry and grazing incidence X‐ray reflectometry

Wulff

Klimke

Gerova

1995

Surface & Interface Analysis

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Magnesium oxide thin films were deposited at an average evaporation rate of 1.8 nm s-' onto different crystalline alumina substrates and amorphous float glass. The deposits were made in an electron-beam evaporator at substrate temperatures between 25OC and 190°C under different oxygen partial pressures. Films of 0.1, 0.5 and 1 pm thickness were deposited. These coatings were investigated by grazing incidence diffractometry (GID) to vary the depth of penetration. For films 0.1 pm thick the additional use of grazing incidence x-ray reflectometry (GIXR) was possible. The deposited films were polycrystalline with different (100) textures depending on the substrate temperature. All the MgO thin-film reflexes measured were strongly broadened compared with the reflexes of a standard polycrystalline MgO material. The crystal size and the microstrain of the MgO coatings were calculated by profile analysis using the Fourier transformation method. It was demonstrated that the x-ray profiles of the MgO reflexes are influenced by the roughness of the substrate surface. Only small gradients were found in the particle sizes and microstrains within the deposited films. The oxygen partial pressure did not significantly influence the film properties measured by GID. The GIXR roughness and mass density measurements agreed with the results of GID. Magnesium oxide films deposited at higher temperatures show a diminished crystallinity and less interface roughness.

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“…In addition, buffer layers are sometimes used to prevent interdiffusion between YBa 2 Cu 3 O 7 À d and the reactive substrate [2]. Various buffer layers have been used including yttria-stabilized zirconia (YSZ) [3], MgAl 2 O 4 , SrTiO 3 [4], MgO [5], etc.…”

Section: Introductionmentioning

confidence: 99%