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dc.contributor.authorMishra, S. K.eng
dc.contributor.authorPandit, Rahuleng
dc.contributor.authorSatpathy, Sashi Sekhar, 1956-eng
dc.date.issued1999eng
dc.descriptiondoi: 10.1088/0953-8984/11/43/320eng
dc.description.abstractWe study phase transitions in the colossal-magnetoresistive manganites by using a mean-field theory both at zero and non-zero temperatures. Our Hamiltonian includes double-exchange, superexchange, and Hubbard terms with on-site and nearest-neighbour Coulomb interaction, with the parameters estimated from earlier density-functional calculations. The phase diagrams show magnetic and charge-ordered (or charge-disordered) phases as a result of the competition between the double-exchange, superexchange, and Hubbard terms, the relative effects of which are sensitively dependent on parameters such as doping, bandwidth, and temperature. In accord with the experimental observations, several important features are reproduced from our model, namely, (i) a phase transition from an insulating, charge-ordered antiferromagnetic to a metallic, charge-disordered ferromagnetic state near dopant concentration x = 1/2, (ii) the reduction of the transition temperature TAFrightarrow F by the application of a magnetic field, (iii) melting of the charge order by a magnetic field, and (iv) phase coexistence for certain values of temperature and doping. An important feature, not reproduced in our model, is the antiferromagnetism in the electron-doped systems, e.g., La1-xCaxMnO3 over the entire range of 0.5le xle1, and we suggest that a multi-band model which includes the unoccupied t2g orbitals might be an important ingredient for describing this feature.eng
dc.description.sponsorshipThis work was supported in part by the Office of Naval Research under contract No ONR N00014-95-1-0439. One of us (RP) thanks the Department of Physics, University of Missouri- Columbia for hospitality, during the time that this work was done, and UGC (India).eng
dc.identifier.citationS K Mishra et al 1999 J. Phys.: Condens. Matter 11 8561eng
dc.identifier.issn0953-8984eng
dc.identifier.urihttp://hdl.handle.net/10355/9445eng
dc.languageEnglisheng
dc.publisherInstitute of Physicseng
dc.relation.ispartofcollectionUniversity of Missouri--Columbia. College of Arts and Sciences. Department of Physics and Astronomy. Physics and Astronomy publicationseng
dc.subjectcolossal magnetoresistanceeng
dc.subjectmagnetic phase boundarieseng
dc.subjectexchange and superexchange interactionseng
dc.subject.lcshMagnetoresistanceeng
dc.subject.lcshManganiteeng
dc.titleMean-field theory of charge ordering and phase transitions in the colossal-magnetoresistive manganiteseng
dc.typeArticleeng


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