Generation of even harmonics in a MgB{sub 2} bulk superconductor: an indication of the presence of weak link grain boundaries Khare, Neeraj [National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110012 (India)]; Singh, D P [National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110012 (India)]; Gupta, A K [National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110012 (India)]; Aswal, D K [Bhabha Atomic Research Centre, Mumbai-400085 (India)]; Sen, Shashawati [Bhabha Atomic Research Centre, Mumbai-400085 (India)]; Gupta, S K [Bhabha Atomic Research Centre, Mumbai-400085 (India)]; Gupta, L C [Tata Institute of Fundamental Research, Mumbai-400005 (India)] 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMPLITUDES; GRAIN BOUNDARIES; HARMONIC GENERATION; MAGNESIUM BORIDES; MAGNETIC FIELDS; POLYCRYSTALS; SUPERCONDUCTORS; VARIATIONS In this paper we report the generation of higher harmonics in a bulk polycrystalline MgB{sub 2} superconductor when it is subjected to ac and dc magnetic field. The MgB{sub 2} sample shows the generation of higher odd harmonics when an ac field is applied. The application of a small dc field (few gauss) in addition to an ac field also leads to the generation of second and fourth harmonics, which is an indication of the presence of some weak link grain boundaries in a MgB{sub 2} superconductor. We have studied the variation of the amplitude of higher harmonics with temperature for different values of amplitude of ac field. The observed results are interpreted in terms of weak link grain boundaries and a critical state model. Available online at http://stacks.iop.org/0953-2048/17/1372/sust4_12_002.pdf or at the Web site for the journal Superconductor Science and Technology (ISSN 1361-6668) http://www.iop.org/;INIS United Kingdom 2004-12-01 English Journal Article Journal Name: Superconductor Science and Technology; Journal Volume: 17; Journal Issue: 12; Other Information: PII: S0953-2048(04)81791-3; DOI: 10.1088/0953-2048/17/12/002; Country of input: International Atomic Energy Agency (IAEA); PBD: 1 Dec 2004 Medium: X; Size: page(s) 1372-1375 https://doi.org/10.1088/0953-2048/17/12/002 [] 12 17 Journal ID: ISSN 0953-2048; SUSTEF; TRN: GB04P5279039647 GBN 2010-12-31 20592710