%0 Journal Article
%A Alonso, J. L.
%A Fernández Pérez, Luis Antonio
%A Guinea, F
%A Laliena, V.
%A Martín Mayor, Víctor
%T Discontinuous transitions in double-exchange materials
%D 2001
%@ 1098-0121
%U https://hdl.handle.net/20.500.14352/60058
%X It is shown that the double-exchange Hamiltonian, with weak antiferromagnetic interactions, has a rich variety of first-order transitions between phases with different electronic densities and/or magnetizations. The paramagnetic-ferromagnetic transition moves towards lower temperatures, and becomes discontinuous as the relative strength of the double-exchange mechanism and antiferromagnetic coupling is changed. This trend is consistent with the observed differences between compounds with the same nominal doping, such as La_(2/3)Sr_(1/3)MnO_(3) and La_(2/3)Ca_(1/3)MnO_(3). Our results suggest that, in the low doping regime, a simple magnetic mechanism suffices to explain the main features of the phase diagram.
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