arXiv subjects

Bernhard Holzapfel

Publications and source records attributed to Bernhard Holzapfel.

21 records · Page 2Linked to original sources

arXiv2010

Epitaxial Growth of Superconducting Ba(Fe1-xCox)2As2 Thin Films on Technical IBAD-MgO Substrates

The biaxially textured growth of superconducting Co-doped BaFe2As2 (Ba-122) thin films has been realized on ion beam assisted deposition (IBAD) MgO coated conductor templates by employing an iron buffer architecture. The iron pnictide coated conductor showed a superconducting transition temperature of 21.5 K, which is slightly lower than that of Co-doped Ba-122 films on single crystalline MgO substrates. A self-field critical current density of over 10^5 A/cm2 has already been achieved even at 8 K. The current experiment highlights the potential of possible coated conductor applications of the iron-based superconductors.

cond-mat.supr-con↗

arXiv2010

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.

cond-mat.supr-con↗

arXiv2010

Coherent interfacial bonding on the FeAs tetrahedron in Fe/Ba(Fe(1-x)Co(x))2As2 bilayers

We demonstrate the growth of epitaxial Fe/Ba(Fe(1-x)Co(x))2As2 (Fe/Ba-122) bilayers on MgO(001) and LSAT(001) single crystal substrates using Pulsed Laser Deposition (PLD). By exploiting the metallic nature of the FeAs tetrahedron in the Ba-122 crystal structure, we achieve a coherent interfacial bond between bcc iron and Co-doped Ba-122. Tc values for both bilayers were close to that of the PLD target. Direct observation of interfacial bonding between Fe and the Ba-122 FeAs sublattice by atomic resolution transmission electron microscopy implies that this bilayer architecture may work for other iron pnictide systems and pave the way for the fabrication of superconducting/ferromagnetic heterostructures.

cond-mat.supr-con↗