106 research outputs found
BaFe2As2/Fe bilayers with [001]-tilt grain boundary on MgO and SrTiO3 bicrystal substrates
Co-doped BaFe2As2 (Ba-122) can be realized on both MgO and SrTiO3 bicrystal
substrates with [001]-tilt grain boundary by employing Fe buffer layers.
However, an additional spinel (i.e. MgAl2O4) buffer between Fe and SrTiO3 is
necessary since an epitaxial, smooth surface of Fe layer can not be grown on
bare SrTiO3. Both types of bicrystal films show good crystalline quality.Comment: Accepted for the ISS2012 Proceedins, a special issue of Physics
Procedi
Properties of Mg-doped Nd-Ba-Cu-O generic seed crystals for the top seeded melt growth of (RE)-Ba-Cu-O bulk superconductors
We have recently developed a new generic seed crystal that has been used successfully to fabricate any oriented, single grain (RE)-Ba-Cu-O bulk superconductor by a cold seeding technique. In this paper we report the chemical, structural and microstructural properties of these seed crystals, including the variation of melting point, crystallographic parameters and volume fraction of Mg-rich inclusions in the Nd1 + xBa 2-x(Cu1-yMgy)3Oz matrix as a function of externally added MgO content. The influence of Mg-doping on the superconducting transition temperatures of YBCO grains fabricated using these seeds is investigated. Finally, an optimum MgO content of the generic seed that effectively controls the orientation of the seeded grain without compromising its superconducting properties is suggested from the many seed crystals fabricated with a wide range of Mg-rich addition
Reversible shift in the superconducting transition for La1.85Sr0.15CuO4 and BaFe1.8Co0.2As2 using piezoelectric substrates
The use of piezoelectric substrates enables a dynamic observation of strain
dependent properties of functional materials. Based on studies with
La1.85Sr0.15CuO4 we extended this approach to the iron arsenic superconductors
represented by BaFe2-xCoxAs2 to investigate strain driven changes in detail. We
demonstrate that epitaxial thin films can be prepared on
(001)Pb(Mg1/3Nb2/3)0.72Ti0.28O3 substrates using pulsed laser deposition. The
structural as well as the electric properties of the grown films were
characterized in detail. A reversible shift of the superconducting transition
of 0.44 K for La1.85Sr0.15CuO4 and 0.2 K for BaFe1.8Co0.2As2 was observed
applying a biaxial strain of 0.022% and 0.017% respectively
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