Abstract
The colossal magnetoresistance (CMR) observed in the oxypnictide NdMnAsO1−xFx has been further investigated. The magnetotransport is dominated by magnetopolarons. Magnetoresistance measurements of the series Nd(Mn1−xCox)AsO0.95F0.05 show that doping with cobalt on the manganese site pins the magnetopolarons and suppresses the CMR, which is completely destroyed by x = 0.047. The chemical doping results in non-stoichiometric samples, with both As and O vacancies. The relationship between the non-stoichiometry, magnetic order, electron doping and CMR is explored. The Nd antiferromagnetic transition and simultaneous reorientation of the Mn spins into the basal plane at 23 K (TSR) is not effected by Co doping. However, there is a significant decrease in TN(Mn) as the antiferromagnetic transition is suppressed from 360 K to 300 K as x increases from 0–0.047. The manganese moment at 10 K is also reduced from 3.86(2)μB to 3.21(2)μB over the same doping range. This reduction in the in-plane Mn moment decreases the electron–electron correlations below TSR and acts to further diminish the magnetoresistance.
Original language | English |
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Pages (from-to) | 14726-14733 |
Number of pages | 8 |
Journal | Dalton Transactions |
Volume | 47 |
Issue number | 41 |
Early online date | 28 Sep 2018 |
DOIs | |
Publication status | Published - 7 Nov 2018 |
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Abbie McLaughlin
- School of Natural & Computing Sciences, Chemistry - Personal Chair
- Centre for Energy Transition
Person: Academic