26 research outputs found
Ambient Temperature Growth and Superconducting Properties of Ti-V Alloy Thin Films
A study on the optimization of ambient temperature growth and superconducting
properties of Ti-V alloy thin films grown on SiO2-coated Si substrate is
reported here. These films have been synthesized by co-sputtering of Ti and V
targets, and films having different Ti concentrations were deposited to get the
optimized critical temperature (TC) of thin films close to the bulk value. The
maximum TC of 5.2 K has been obtained in the Ti40V60 composition, which is
further increased to 6.2 K when a 10 nm thick Ti underlayer is added below the
Ti-V film. GIXRD measurements confirm the formation of Ti-V alloys in the
desired crystal structure. The upper critical field (HC2) of the thin films has
been estimated with the help of magnetotransport measurements. The utility of
Ti-V alloy thin films in superconducting radiation detection applications is
ascertained.Comment: 4 pages, 6 figure
Upper critical field anisotropy in BaFe2-xCoxAs2 single crystals synthesized without flux
The upper critical field was measured upto 12 T for three BaFe2-xCoxAs2
single crystals with estimated Co concentrations of x = 0.082, x = 0.117 and x
= 0.143. HC2 versus temperature was measured from temperature dependent
resistivity, for various applied magnetic fields, H || ab and H || c. The
[dHC2/dT]T=Tc, normalized with the corresponding TC, decreases with increasing
Co content, for both directions. The anisotropy {\gamma} defined as HC2 || ab /
HC2 || c shows a distinct increase with Co content, and its temperature
dependence shows a peak close to the TC. Magneto transport measurements, in the
spin density wave regions, showed significant negative MR for H || ab and
positive MR of H || c in the x = 0.082 sample. The implications of these
results are discussed.Comment: 12 pages 7 figure
Critical current density and magnetic phase diagram of BaFe1.29Ru0.71As2 Single Crystals
The critical current density has been measured on single crystals of Ru
substituted BaFe2As2 superconductor at several temperatures and in fields up to
16 T. The magnetisation versus field isotherms reveal the occurrence of a clear
second magnetisation peak (SMP) also known as fish-tail effect for both H
parallel and perpendicular to c-axis of the crystal. The in-field resistance
and magnetisation data are used to put forth a vortex phase diagram. The nature
of the vortices have been determined from scaling behaviour of the pinning
force density extracted from the Jc-H isotherms. The scaled JC versus reduced
temperature behaviour seems to fit to a power law that indicates unambiguously
that pinning in this system arises due to the spatial variation in the mean
free path, viz. delta-l pinning