Tailor-made electronic and magnetic properties in one-dimensional pure and Y-substituted Ca3Co2O6

R Vidya; P Ravindran; H Fjellvåg; A Kjekshus; O Eriksson

doi:10.1103/PhysRevLett.91.186404

Tailor-made electronic and magnetic properties in one-dimensional pure and Y-substituted Ca3Co2O6

Phys Rev Lett. 2003 Oct 31;91(18):186404. doi: 10.1103/PhysRevLett.91.186404. Epub 2003 Oct 30.

Authors

R Vidya¹, P Ravindran, H Fjellvåg, A Kjekshus, O Eriksson

Affiliation

¹ Department of Chemistry, University of Oslo, Box 1033 Blindern, N-0315 Oslo, Norway. vidya.ravindran@kjemi.uio.no

PMID: 14611297
DOI: 10.1103/PhysRevLett.91.186404

Abstract

Full-potential density-functional calculations show that the electronic structure of one-dimensional ferrimagnetic Ca3Co2O6 varies from metal to half metal to insulator as its magnetic ordering changes from the ferrimagnetic through the ferromagnetic to the paramagnetic state. The present Letter is the first to establish the occurrence of half metallicity in one-dimensional oxides. Moreover, the electronic and magnetic properties of this material can be tuned by substitution of Y for Ca, as shown by our detailed study on Ca(3-x)YxCo2O6 (x = 0, 0.3, 0.75, and 1). The Co ions are in two different valence states [Co4+ (low-spin) and Co2+ (high-spin)], and hence the occurrence of charge ordering in addition to spin ordering is established. For specific Y concentrations we predict a rarely seen combination of ferromagnetic and insulating behavior.