Coexistence of intrinsic and extrinsic magnetoresistance in the double-perovskite Sr[sub 2]Fe(Mo[sub 1-x]W[sub x])O[sub 6-w] system

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Volume Title
School of Chemical Technology | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2001
Major/Subject
Mcode
Degree programme
Language
en
Pages
2736-2738
Series
Applied Physics Letters, Volume 78, Issue 18
Abstract
In a recent study, it was shown that by partially substituting Mo with W in the double-perovskite Sr2FeMoO6−w system, the magnetoresistivity can be enhanced. [K.-I. Kobayashi, T. Okuda, Y. Tomioka, T. Kimura, and Y. Tokura, J. Magn. Magn. Mater. 218, 17 (2000).] In order to explain the increase in the magnetoresistivity a series of W-substituted Sr2Fe(Mo1−xWx)O6−w samples with 0⩽x⩽1 was synthesized. Upon increasing the W content, the samples began to exhibit coexistence of paramagnetism and ferrimagnetism at 300 K. Signatures of antiferromagnetic ordering appeared around TN≈50 K for x⩾0.6. In samples with 0.7⩽x⩽0.8 a broad peak was observed in the magnetoresistance data at temperatures corresponding to the Néel temperature. The peak was found to have its origin in the colossal magnetoresistanceeffect. The W-substituted samples were partially ferrimagnetic and therefore also exhibited the tunneling-type magnetoresistance, which is characteristic of pure Sr2FeMoO6−w. The coexistence of the two types of magnetoresistanceeffect is responsible for the enhancement of the overall magnetoresistance value. A slight enhancement in the magnetoresistance values around 300 K for the strongly W-substituted samples was found to be related to a second colossal magnetoresistance peak related to the para- to ferrimagnetic transition at Tc.
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Keywords
ferrimagnetism, magnetoresistance, molybdenum, perovskites
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Citation
Lindén, J. & Yamamoto, T. & Nakamura, J. & Karppinen, Maarit & Yamauchi, H.. 2001. Coexistence of intrinsic and extrinsic magnetoresistance in the double-perovskite Sr[sub 2]Fe(Mo[sub 1-x]W[sub x])O[sub 6-w] system. Applied Physics Letters. Volume 78, Issue 18. 2736-2738. ISSN 0003-6951 (printed). DOI: 10.1063/1.1366357.