Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail

Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail

In this study, two series of superconductor compounds with starting composition T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0—0.20) and T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) ceramics were prepared using the conventional solid state synthesis method to elucidate their physica...

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Main Author: Ismail, Shabani
Format: Thesis
Language:English
Published: 2015
Subjects:
Superconductivity physics
Superconducting materials. Superconductors
Online Access:http://ir.uitm.edu.my/id/eprint/15664/
http://ir.uitm.edu.my/id/eprint/15664/1/TP_SHABANI%20ISMAIL%20AS%2015_5.pdf
id uitm-15664
recordtype eprints
repository_type Digital Repository
institution_category Local University
institution Universiti Teknologi MARA
building UiTM Institutional Repository
collection Online Access
language English
topic Superconductivity physics
Superconducting materials. Superconductors
spellingShingle Superconductivity physics
Superconducting materials. Superconductors
Ismail, Shabani
Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail
description In this study, two series of superconductor compounds with starting composition T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0—0.20) and T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) ceramics were prepared using the conventional solid state synthesis method to elucidate their physical properties. For Ce-substituted of T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0—0.20) samples, the zero critical temperature, Tczero increased from 65.4 K (x = 0.05) to 71.0 K (x = 0.10), but slightly decreased for x > 0.10 indicating the optimum value of average copper valence was achieved at x = 0.10. Excess conductivity analysis using the Aslamazov Larkin, AL and Lawrence-Doniach, LD models revealed two dimensional, 2D to threedimensional, 3D transition of superconducting fluctuation behavior, SFB with the highest transition temperature, T2D-3D at x = 0.10. FTIR analysis in conjunction with XRD results showed softening of FeO2/CuO2 planar oxygen mode which is suggested to be related to possible increase of interplane coupling, J and this is supported by computed results based on the LD model. The enhanced J increases superconducting coherence length along c-axis, ^c(0), and hence lowers anisotropy, y resulting in enhanced superconducting properties. For T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) ceramics, substitution of Cd caused Tc zero increasing from 40.0 K (x = 0) to 76.4 K (x = 0.3) before decreasing to 74.8 K (x = 0.4) with increasing Cd2+ contents. FTIR analysis in conjunction with XRD results indicates improved J that is evidenced in the form of decreased c-axis length and softening of the apical oxygen mode with Cd concentration. Excess conductivity analyses showed cross-over between 2D to 3D SFB transition for all the samples (x = 0.1-0.4) with the highest T2D-3D was observed at x = 0.3. Similar calculation revealed longest value of §c(0) and the highest J at x = 0.3. Ultrasonic velocity measurements was performed on longitudinal and shear velocities at 9 MHz in temperature ranges of 80-280 K and 80-220 K, respectively, for T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) and T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0-0.20) ceramics to study the influence of Cd and Ce substitutions on elastic properties and elastic anomaly. For the former series, ultrasonic velocity measurements at 80 K showed a non-linear increase in both absolute longitudinal and shear velocities as well as elastic moduli with Cd substitution with the largest increase observed for the x = 0.3 sample. Temperature dependant longitudinal modulus showed elastic anomaly characterized by a step-like slope change at around 230 K for x = 0 & x = 0.3 and at around 250 K for x = 0.4 with the x = 0.3 sample showing the sharpest slope change. For T1.09Bi0.1Sr2-xCexCa0.9Y0.1Cu1.9 9Fe0.01O7.g series, Ce was observed to influence elastic moduli at 80K which showed the largest value obtained at x = 0.10. A longitudinal velocity anomaly was observed at around 260 K for the unsubstituted sample (x = 0). Ce substitution caused the temperature of the elastic anomaly to shift to 250 K (x = 0.1) and 262 K (x = 0.2). The existence of the step-like elastic anomaly was suggested to be due to oxygen ordering taking place in Tl-0 planes. The analysis of the elastic behavior in the vicinity of the elastic anomalies using Landau free-energy model for both T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) and T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0-0.20) series suggests that the anomaly is due to a phase transition which involves oxygen ordering.
format Thesis
author Ismail, Shabani
author_facet Ismail, Shabani
author_sort Ismail, Shabani
title Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail
title_short Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail
title_full Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail
title_fullStr Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail
title_full_unstemmed Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail
title_sort effects of ce4+ and cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of fe-doped (t1,bi)-1212 high temperature superconductors / shabani ismail
publishDate 2015
url http://ir.uitm.edu.my/id/eprint/15664/
http://ir.uitm.edu.my/id/eprint/15664/1/TP_SHABANI%20ISMAIL%20AS%2015_5.pdf
first_indexed 2023-09-18T22:54:22Z
last_indexed 2023-09-18T22:54:22Z
_version_ 1777417754880507904
spelling uitm-156642016-12-18T04:21:07Z http://ir.uitm.edu.my/id/eprint/15664/ Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail Ismail, Shabani Superconductivity physics Superconducting materials. Superconductors In this study, two series of superconductor compounds with starting composition T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0—0.20) and T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) ceramics were prepared using the conventional solid state synthesis method to elucidate their physical properties. For Ce-substituted of T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0—0.20) samples, the zero critical temperature, Tczero increased from 65.4 K (x = 0.05) to 71.0 K (x = 0.10), but slightly decreased for x > 0.10 indicating the optimum value of average copper valence was achieved at x = 0.10. Excess conductivity analysis using the Aslamazov Larkin, AL and Lawrence-Doniach, LD models revealed two dimensional, 2D to threedimensional, 3D transition of superconducting fluctuation behavior, SFB with the highest transition temperature, T2D-3D at x = 0.10. FTIR analysis in conjunction with XRD results showed softening of FeO2/CuO2 planar oxygen mode which is suggested to be related to possible increase of interplane coupling, J and this is supported by computed results based on the LD model. The enhanced J increases superconducting coherence length along c-axis, ^c(0), and hence lowers anisotropy, y resulting in enhanced superconducting properties. For T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) ceramics, substitution of Cd caused Tc zero increasing from 40.0 K (x = 0) to 76.4 K (x = 0.3) before decreasing to 74.8 K (x = 0.4) with increasing Cd2+ contents. FTIR analysis in conjunction with XRD results indicates improved J that is evidenced in the form of decreased c-axis length and softening of the apical oxygen mode with Cd concentration. Excess conductivity analyses showed cross-over between 2D to 3D SFB transition for all the samples (x = 0.1-0.4) with the highest T2D-3D was observed at x = 0.3. Similar calculation revealed longest value of §c(0) and the highest J at x = 0.3. Ultrasonic velocity measurements was performed on longitudinal and shear velocities at 9 MHz in temperature ranges of 80-280 K and 80-220 K, respectively, for T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) and T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0-0.20) ceramics to study the influence of Cd and Ce substitutions on elastic properties and elastic anomaly. For the former series, ultrasonic velocity measurements at 80 K showed a non-linear increase in both absolute longitudinal and shear velocities as well as elastic moduli with Cd substitution with the largest increase observed for the x = 0.3 sample. Temperature dependant longitudinal modulus showed elastic anomaly characterized by a step-like slope change at around 230 K for x = 0 & x = 0.3 and at around 250 K for x = 0.4 with the x = 0.3 sample showing the sharpest slope change. For T1.09Bi0.1Sr2-xCexCa0.9Y0.1Cu1.9 9Fe0.01O7.g series, Ce was observed to influence elastic moduli at 80K which showed the largest value obtained at x = 0.10. A longitudinal velocity anomaly was observed at around 260 K for the unsubstituted sample (x = 0). Ce substitution caused the temperature of the elastic anomaly to shift to 250 K (x = 0.1) and 262 K (x = 0.2). The existence of the step-like elastic anomaly was suggested to be due to oxygen ordering taking place in Tl-0 planes. The analysis of the elastic behavior in the vicinity of the elastic anomalies using Landau free-energy model for both T10.9Bi0.1Sr1.8Yb0.2Ca1.xCdxCu1.99Fe0.01O7-o (x - 0-0.4) and T10.9Bi0.1Sr2-xCexCa0.9Y0.1Cu1.99Fe0.01O7-o (x = 0-0.20) series suggests that the anomaly is due to a phase transition which involves oxygen ordering. 2015 Thesis NonPeerReviewed text en http://ir.uitm.edu.my/id/eprint/15664/1/TP_SHABANI%20ISMAIL%20AS%2015_5.pdf Ismail, Shabani (2015) Effects of Ce4+ and Cd2+ substitutions on superconducting fluctuation behavior, ultrasonic velocity and elastic properties of Fe-Doped (T1,Bi)-1212 high temperature superconductors / Shabani Ismail. PhD thesis, Universiti Teknologi MARA.

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