Absence of Colossal Magnetoresistance in the Oxypnictide PrMnAsO0.95F0.05

We have recently reported a new mechanism of colossal magnetoresistance (CMR) in electron doped manganese oxypnictides NdMnAsO1–x F x . Magnetoresistances of up to −95% at 3 K have been observed. Here we show that upon replacing Nd for Pr, the CMR is surprisingly no longer present. Instead a sizable...

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Bibliographic Details
Published inInorganic chemistry Vol. 54; no. 6; pp. 2536 - 2542
Main Authors Wildman, Eve J, Sher, Falak, Mclaughlin, Abbie C
Format Journal Article
LanguageEnglish
Published United States American Chemical Society 16.03.2015
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Summary:We have recently reported a new mechanism of colossal magnetoresistance (CMR) in electron doped manganese oxypnictides NdMnAsO1–x F x . Magnetoresistances of up to −95% at 3 K have been observed. Here we show that upon replacing Nd for Pr, the CMR is surprisingly no longer present. Instead a sizable negative magnetoresistance is observed for PrMnAsO0.95F0.05 below 35 K (MR7T (12 K) = −13.4% for PrMnAsO0.95F0.05). A detailed neutron and synchrotron X-ray diffraction study of PrMnAsO0.95F0.05 has been performed, which shows that a structural transition, T s, occurs at 35 K from tetragonal P4/nmm to orthorhombic Pmmn symmetry. The structural transition is driven by the Pr 4f electrons degrees of freedom. The sizable −MR observed below the transition most likely arises due to a reduction in magnetic and/or multipolar scattering upon application of a magnetic field.
ISSN:0020-1669
1520-510X
DOI:10.1021/ic502445t