Effect of high-pressure annealing on magnetoresistance in manganese perovskites

Y. H. Huang*, M. Karppinen, H. Yamauchi, J. B. Goodenough

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

Through high-pressure (HP) annealing, a large enhancement of the magnetoresistance (MR) has been achieved for polycrystalline La0.7 Sr0.3 Mn O3 samples over a wide range of temperature at low applied magnetic fields. Moreover, the HP-annealed samples exhibit much lower resistivity and higher metal-insulator transition temperatures. Interestingly, the low-field MR (LFMR*) values at 5 K of such HP-annealed samples are found to reach as high as 45%, significantly exceeding a theoretical upper limit of 33% based on the second-order tunneling through interfacial spin sites for the polycrystalline manganese oxides. We attribute the enhanced LFMR* to the effect of HP annealing that makes the grain boundary thinner and thus allows a large fraction of eg electrons tunnel directly across the grain boundary rather than by a two-step hop process.

Original languageEnglish
Article number033911
JournalJournal of Applied Physics
Volume98
Issue number3
DOIs
Publication statusPublished - 1 Aug 2005
MoE publication typeA1 Journal article-refereed

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