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Origin and pressure dependence of ferromagnetism in A2Mn2O7 pyrochlores (A=Y, In, Lu, and Tl)

M. D. Nunez-Regueiro·C. Lacroix
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Abstract

Non-conventional mechanisms have been recently invoked in order to explain the ferromagnetic ground state of A2Mn2O7 pyrochlores (A=Y, In, Lu and Tl) and the puzzling decrease of their Curie temperatures with applied pressure. Here we show, using a perturbation expansion in the Mn-O hopping term, that both features can be understood within the superexhange model, provided that the intra-atomic oxygen interactions are properly taken into account. An additional coupling between the Mn ions mediated by the In(5s)/Tl(6s) bands yields the higher Tc's of these two compounds, this mechamism enhancing their ferromagnetism for higher pressures.

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M. D. Nunez-Regueiro, C. Lacroix. 2000-07-11. Origin and pressure dependence of ferromagnetism in A2Mn2O7 pyrochlores (A=Y, In, Lu, and Tl). https://doi.org/10.1103/physrevb.63.014417

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