Texture effect on vortex-state TF-^+SR in Bi-2223 high-T_C materials

Authors: Grynszpan R.I.¹; Langlois P.L.²; Noakes D.R.¹; Stronach C.E.¹; Granderson M.M.¹; Ansaldo E.J.³; Brownstein J.R.⁴; Hill A.J.⁵; Bastow T.J.⁶

Source: Hyperfine Interactions, Volume 105, Numbers 1-4, 1997 , pp. 95-100(6)

Publisher: Springer

Abstract:

The influence of texture in Bi-2223 ingots on the temperature dependence of the ^+ spin relaxation rate has been investigated. Texture was induced during cold-isostatic-pressing by applying an additional uniaxial load which tends to align single grain c axes along the stress direction, \widehatz. Small plates were cut with faces either \Vert or \perp \widehatz and SRwas measured in a 15 mT transverse field (TF) during cooling from room temperature to 6 K. While for highly-textured material, low-temperature limits are substantially smaller than expected, the large shift (55%) observed when switching from \widehatz\perp TF to \widehatz\,\Vert TF clearly indicates that anisotropy has developed. Relaxation rates for the weakly-textured sample lie in between. To a lesser extent, sintering also enhanced the low-temperature relaxation, but did not affect T_C significantly. All samples showed a weak onset of depolarization between 60 K and 90 K, most likely due to the presence of a Bi-2212 impurity phase. This impurity phase might cause the transition-temperature smearing in the 100–110 K range in the weakly textured (and less compacted) material. Thus the sharpness of the relaxation drop might be relevant for assessment of material quality and be used as a criterion in the improvement of the production process.

Language: English

Document Type: Regular paper

Affiliations: 1: Physics Department, Virginia State University, Petersburg, VA 23806, USA 2: Laboratoire de PhysicoChimie des Matériaux, CNRS-UPR 211, Meudon, France 3: Physics Department, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 0W0 4: Physics Department, University of British Columbia, Vancouver, BC, Canada V6T 2A3 5: Faculty of Engineering, Monash University, Clayton, Victoria 3168, Australia 6: Division of Materials Science and Technology, CSIRO, Clayton, Victoria 3169, Australia

Publication date: 1997-01-01

• In this: publication
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• In this Subject: Electricity & Magnetism
• By this author: Grynszpan R.I. ;  Langlois P.L. ;  Noakes D.R. ;  Stronach C.E. ;  Granderson M.M. ;  Ansaldo E.J. ;  Brownstein J.R. ;  Hill A.J. ;  Bastow T.J.

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