Open AccessНовая магнитная нецентральная примесь --- кобальт в титанате стронция
Author(s) -
И.А. Случинская,
А.И. Лебедев
Publication year - 2019
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2019.03.47245.300
Subject(s) - cobalt , impurity , x ray absorption fine structure , materials science , a site , ion , crystallography , chemistry , spectroscopy , analytical chemistry (journal) , inorganic chemistry , physics , binding site , biochemistry , organic chemistry , chromatography , quantum mechanics
The local structure and charge state of the cobalt impurity in SrTiO_3 is studied by X-ray absorption fine structure (XAFS) spectroscopy. The synthesis conditions, under which cobalt predominantly (up to 76%) substitutes the atoms at the A site of the perovskite structure, is found for SrTiO_3(Co) samples. By varying the synthesis conditions, it is possible to appreciably change the ratio between the concentrations of cobalt atoms incorporated into the A and B sites. It is established that the charge state of cobalt is +2 at the A site and +3 at the B site. It is revealed that the Co impurity at the A site is off-center, and its deviation from the lattice site is 1.0 Å. First-principles calculations show that the isolated Co^3+ ion at the B site is diamagnetic, whereas the Co^2+ ion at the A site is in a high-spin state ( S = 3/2).