DSpace
 

DSpace at IIT Bombay >
IITB Publications >
Proceedings papers >

Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/100/1626

Title: Peak effect phenomena, surface superconductivity and paramagnetic Meissner effect in a spherical single crystal of niobium
Authors: DAS, P
TOMY, CV
TAKEYA, H
RAMAKRISHNAN, S
GROVER, AK
Keywords: nb
lattice
Issue Date: 2009
Publisher: IOP PUBLISHING LTD
Citation: 25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25), PART 5: SUPERCONDUCTIVITY,150,-
Abstract: We have explored the vortex phase diagram in a spherical single crystal of niobium (T(c) similar to 9.3 K) via isothermal and temperature dependent dc magnetization and ac-susceptibility measurements. The crystal has extremely weak pinning that can be inferred from the reversibility of M - H loops below T(c). However, one can visualize the peak effect (PE) feature in the isothermal M - H loops up to T = 8 K. The PE is also prominent in isothermal ac-susceptibility data for H > 750 Oe. An interesting observation in the present study is the prominent fingerprints of surface superconductivity, starting just above the collapse of pinning at the peak position of the PE and ending at the surface critical field (H(c3)). We have also observed the paramagnetic Meissner effect in field-cooled magnetization data recorded at relatively large fields in this crystal. A vortex phase diagram is constructed by marking the peak positions of the PE (H(p)), the upper critical field (H(c2)) and the surface critical field (H(c3)). Unlike a previous report which shows the existence of a multi-critical point in the phase diagram of a Nb crystal, where H(p), H(c2) and H(c3) lines meet, we do not observe a multi-critical point in our weak pinning crystal.
URI: http://dx.doi.org/10.1088/1742-6596/150/5/052041
http://dspace.library.iitb.ac.in/xmlui/handle/10054/14951
http://hdl.handle.net/100/1626
ISSN: 1742-6588
Appears in Collections:Proceedings papers

Files in This Item:

There are no files associated with this item.

View Statistics

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback