Discontinuous transitions in double-exchange materials



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Alonso, J. L. and Fernández Pérez, Luis Antonio and Guinea, F and Laliena, V. and Martín Mayor, Víctor (2001) Discontinuous transitions in double-exchange materials. Physical review B, 63 (6). ISSN 1098-0121

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Official URL: http://doi.org/10.1103/PhysRevB.63.064416


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.

Item Type:Article
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© 2001 American Physical Society. We are thankful for helpful conversations to L. Brey, J. Fontcuberta, G. Gómez-Santos, C. Simon, J. M. De Teresa, and especially to R. Ibarra. V.M.-M. acknowledges the financial support of MEC. The Monte Carlo simulations have been carried out in RTNN computers at Zaragoza and Madrid. We acknowledge financial support from Grant Nos. PB96-0875, AEN97-1680, AEN97-1693, AEN99-0990 (MEC, Spain), and (07N/0045/98) (C. Madrid).

Uncontrolled Keywords:Inelastic-neutron-scattering; Metal-insulator-transition; Mixed-valence manganites; Spectral moments method; colossal-magnetoresistance; Phase-separation; Manganese perovskites; Spin dynamics; Ferromagnetic manganites; Charge localization.
Subjects:Sciences > Physics
Sciences > Physics > Physics-Mathematical models
ID Code:40079
Deposited On:17 Nov 2016 10:55
Last Modified:17 Nov 2016 10:55

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