Maheshwari, P. K. and Jha, Rajveer and Gahtori, Bhasker and Awana, V. P. S. (2015) Flux free growth of large FeSe1/2Te1/2 superconducting single crystals by an easy high temperature melt and slow cooling method. AIP Advances, 5 (9). 097112-1-097112-10. ISSN 2158-3226
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Abstract
We report successful growth of flux free large single crystals of superconducting FeSe1/2Te1/2 with typical dimensions of up to few cm. The AC and DC magnetic measurements revealed the superconducting transition temperature (T-c) value of around 11.5K and the isothermal MH showed typical type-II superconducting behavior. The lower critical field (H-c1) being estimated by measuring the low field isothermal magnetization in superconducting regime is found to be above 200Oe at 0K. The temperature dependent electrical resistivity rho(T) showed the T-c (onset) to be 14K and the T-c(rho = 0) at 11.5K. The electrical resistivity under various magnetic fields i.e., rho(T)H for H//ab and H//c demonstrated the difference in the width of T-c with applied field of 14Tesla to be nearly 2K, confirming the anisotropic nature of superconductivity. The upper critical and irreversibility fields at absolute zero temperature i.e., H-c2(0) and H-irr(0) being determined by the conventional one-band Werthamer-Helfand-Hohenberg (WHH) equation for the criteria of normal state resistivity (rho(n)) falling to 90% (onset), and 10% (offset) is 76.9Tesla, and 37.45Tesla respectively, for H//c and 135.4Tesla, and 71.41Tesla respectively, for H//ab. The coherence length at the zero temperature is estimated to be above 20 angstrom by using the Ginsburg-Landau theory. The activation energy for the FeSe1/2Te1/2 in both directions H//c and H//ab is determined by using Thermally Activation Flux Flow (TAFF) model.
| Item Type: | Article |
|---|---|
| Subjects: | Materials Science Applied Physics/Condensed Matter Nanoscience/ Nanotechnology |
| Divisions: | UNSPECIFIED |
| Depositing User: | Dr. Rajpal Walke |
| Date Deposited: | 23 Sep 2016 05:53 |
| Last Modified: | 23 Sep 2016 05:53 |
| URI: | http://npl.csircentral.net/id/eprint/1831 |
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