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Transport properties and anisotropy in rare-earth doped CaFe2As2 single crystals with Tc above 40 K.
- Source :
- Semiconductor Science & Technology; Apr2012, p1-7, 7p
- Publication Year :
- 2012
-
Abstract
- In this paper we report the superconductivity above 40 K in the electron doping single crystals Ca<subscript>1−x</subscript>R<subscript>x</subscript>Fe<subscript>2</subscript>As<subscript>2</subscript> (R = La, Ce, Pr). The x-ray diffraction patterns indicate high crystalline quality and c-axis orientation. The resistivity anomaly in the parent compound CaFe<subscript>2</subscript>As<subscript>2</subscript> is completely suppressed by partial replacement of Ca with rare-earth elements and the superconducting transition reaches as high as 46 K, which is higher than the value in electron doping FeAs-122 compounds formed by substituting Fe ions with transition metal, and even surpasses the highest value observed in hole doping systems with a transition temperature up to 38 K. The upper critical fields have been determined with the magnetic field along the ab-plane and c-axis, yielding an anisotropy of 2–3. Hall effect measurements indicate that the conduction in this material is dominated by electron-like charge carriers. Our results confirm the feasibility of inducing superconductivity in Ca122 compounds via electron doping using aliovalent rare-earth substitution into the alkaline earth site, which should add more ingredients to the underlying physics of the iron-based superconductors. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02681242
- Database :
- Complementary Index
- Journal :
- Semiconductor Science & Technology
- Publication Type :
- Academic Journal
- Accession number :
- 78148887