On the strong impact of doping in the triangular antiferromagnet CuCrO2 - Condensed Matter > Strongly Correlated ElectronsReport as inadecuate




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Abstract: Electronic band structure calculations using the augmented spherical wavemethod have been performed for CuCrO2. For this antiferromagnetic T N = 24 Ksemiconductor crystallizing in the delafossite structure, it is found that thevalence band maximum is mainly due to the t 2g orbitals of Cr^3+ and that spinpolarization is predicted with 3 mu B per Cr^3+. The structuralcharacterizations of CuCr1-xMgxO2 reveal a very limited range of Mg^2+substitution for Cr^3+ in this series. As soon as x = 0.02, a maximum of 1% Crions substituted by Mg site is measured in the sample. This result is alsoconsistent with the detection of Mg spinel impurities from X-ray diffractionfor x = 0.01. This explains the saturation of the Mg^2+ effect upon theelectrical resistivity and thermoelectric power observed for x > 0.01. Such avery weak solubility limit could also be responsible for the discrepanciesfound in the literature. Furthermore, the measurements made under magneticfield magnetic susceptibility, electrical resistivity and Seebeck coefficientsupport that the Cr^4+ -holes-, created by the Mg^2+ substitution, in thematrix of high spin Cr^3+ S = 3-2 are responsible for the transportproperties of these compounds.



Author: Antoine Maignan, Christine Martin, Raymond Fresard, Volker Eyert, Emmanuel Guilmeau, Sylvie Hebert, Maria Poienar, Denis Pelloqui

Source: https://arxiv.org/







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