000069456 001__ 69456
000069456 005__ 20191127155457.0
000069456 0247_ $$2doi$$a10.1103/PhysRevB.97.085111
000069456 0248_ $$2sideral$$a104585
000069456 037__ $$aART-2018-104585
000069456 041__ $$aeng
000069456 100__ $$aGarcía, J.
000069456 245__ $$aResonant x-ray scattering study of charge superstructures in layered L a2-x C axCo O4±d (0.4=x=0.7) and L a1.5 S r0.5Co O4 compounds
000069456 260__ $$c2018
000069456 5060_ $$aAccess copy available to the general public$$fUnrestricted
000069456 5203_ $$aWe propose a model for the Co charge disproportionation in La2-xCaxCoO4±d (0.4=x=0.7) and La1.5Sr0.5CoO4 layered cobaltites based on the photon energy, azimuthal angle, and polarization dependence of the scattered intensity of selected reflections in a resonant x-ray scattering experiment. Tetragonal superlattice (h/2, h/2, l)-type reflections were detected at room temperature for all the samples independently from the Ca (or Sr) doping rate in agreement with a checkerboard ordering of two different Co sites. The corresponding average charge disproportion is accounted for by a semiempirical model from which the imaginary part of the resonant atomic scattering factors of each of the two Co atoms is obtained resulting in about 0.5±0.1 electron. Moreover, no forbidden (h/4, h/4, l)-type reflections were observed at room temperature indicating the lack of any local anisotropy ordering in contrast with the behavior found in the related layered manganites. Finally, we found the pattern of small distortions (~0.05Å) around the two Co sites compatible with the resonant x-ray scattering results. The symmetry of this displacement pattern is consistent with the A2mm (or Ammm) orthorhombic structure of the ordered phase and the structural transition is accounted for by the condensation of two soft modes - X1+(B2u) and X1+(A1) - acting on the oxygen atoms.
000069456 536__ $$9info:eu-repo/grantAgreement/ES/DGA/E69$$9info:eu-repo/grantAgreement/ES/MINECO/MAT2015-68760-C2-1-P
000069456 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc$$uhttp://creativecommons.org/licenses/by-nc/3.0/es/
000069456 592__ $$a1.502$$b2018
000069456 593__ $$aElectronic, Optical and Magnetic Materials$$c2018$$dQ1
000069456 593__ $$aCondensed Matter Physics$$c2018$$dQ1
000069456 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000069456 700__ $$0(orcid)0000-0002-9029-1977$$aSubías, G.$$uUniversidad de Zaragoza
000069456 700__ $$0(orcid)0000-0002-9706-3272$$aBlasco, J.$$uUniversidad de Zaragoza
000069456 700__ $$aSánchez, M.C.
000069456 700__ $$aBeutier, G.
000069456 7102_ $$12003$$2395$$aUniversidad de Zaragoza$$bDpto. Física Materia Condensa.$$cÁrea Física Materia Condensada
000069456 773__ $$g97, 8 (2018), 085111 [12 pp]$$pPhys. Rev. B$$tPhysical Review B$$x2469-9950
000069456 8564_ $$s1738363$$uhttps://zaguan.unizar.es/record/69456/files/texto_completo.pdf$$yVersión publicada
000069456 8564_ $$s23924$$uhttps://zaguan.unizar.es/record/69456/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000069456 909CO $$ooai:zaguan.unizar.es:69456$$particulos$$pdriver
000069456 951__ $$a2019-11-27-15:48:13
000069456 980__ $$aARTICLE