Absence of Colossal Magnetoresistance in the Oxypnictide PrMnAsO0.95F0.05
arXiv:1503.07651 · doi:10.1021/ic502445t
Abstract
We have recently reported a new mechanism of colossal magnetoresistance in electron doped Mn oxypnictides NdMnAsO1-xFx. Magnetoresistances of up to -95 percent at 3 K have been observed. Here we show that upon replacing Nd for Pr, the CMR is surprisingly no longer present. Instead a sizeable negative magnetoresistance is observed for PrMnAsO0.95F0.05 below 35 K (MR7T (12 K) = -13.4 percent for PrMnAsO0.9F0.05. A detailed neutron and synchrotron X-ray diffraction study of PrMnAsO0.95F0.05 has been performed, which shows that a structural transition, Ts, 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.
References in corpus (9)
- Superconductivity and Phase Diagram in the Iron-based Arsenic-oxides ReFeAsO1-delta (Re = rare earth metal) without F-Doping
- Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
- Superconductivity at 52 K in iron-based F-doped layered quaternary compound Pr[O1-xFx]FeAs
- Itinerant Ferromagnetism in layered crystals LaCoOX (X = P, As)
- Nickel-based layered superconductor, LaNiOAs
- A variable temperature study of the crystal and magnetic structures of the giant magnetoresistant materials LnMnAsO (Ln = La, Nd)
- Nd induced Mn spin-reorientation transition in NdMnAsO
- Local moments and symmetry breaking in metallic PrMnSbO
- Colossal Magnetoresistance in the Mn2+ Oxypnictides NdMnAsO1-xFx