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Title: Contrasting Effects of Ca{sup 2+} and Ho{sup 3+} Substitutions on Superconductivity and Excess conductivity of (Ho{sub 1-x}Ca{sub x})(Ba{sub 2-y}Ho{sub y})Cu{sub 3}O{sub 7-{delta}}

Journal Article · · AIP Conference Proceedings
DOI:https://doi.org/10.1063/1.3469720· OSTI ID:21415272
; ; ; ;  [1]
  1. Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia)

Effects of Ho{sup 3+} and Ca{sup 2+} substitutions in (Ho{sub 1-x}Ca{sub x})(Ba{sub 2-y}Ho{sub y})Cu{sub 3}O{sub 7-{delta}}ceramics on normal and superconducting state behaviour were investigated. Electrical resistivity measurements showed increasing Ho{sup 3+} substitution at Ba{sup 2+} site (x = 0, 0.4, y = 0-0.4) caused normal state resistivity to change from metal-like to semimetal/semiconductor-like behaviour and suppressed T{sub c} from 89 K (y = 0) to 72 K (y = 0.4) while substitution of Ca{sup 2+} for Ho{sup 3+}((x = 0.2) 0.4, (y 0.4)) revives metallic behaviour of the normal state with increasing x. Excess conductivity analysis based on Asmalazov-Larkin theory showed 2D to 3D transition for all superconducting samples but with contrasting effects of the substitutions on AL{sub 2D} and AL{sub 3D} constants. The resistivity and excess conductivity results indicate effective hole filling Ho{sup 3+} and hole doping by by Ca{sup 2+} substitutions.

OSTI ID:
21415272
Journal Information:
AIP Conference Proceedings, Vol. 1250, Issue 1; Conference: PERFIK2009: National physics conference 2009, Malacca (Malaysia), 7-9 Dec 2009; Other Information: DOI: 10.1063/1.3469720; (c) 2010 American Institute of Physics; ISSN 0094-243X
Country of Publication:
United States
Language:
English