A comprehensive structural analysis of relaxor ferroelectric Cr- and Ni-doped Sr0.61Ba0.39Nb2O6 crystals

• Published in: Journal of alloys and compounds Vol. 724; pp. 879 - 888
• Main Authors: Kuz'micheva, Galina M., Kaurova, Irina A., Khramov, Evgeny V., Ivleva, Liudmila I., Chernyshev, Vladimir V., Rybakov, Victor B.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-11-2017; Elsevier BV
• Subjects: Atomic structure; Chromium; Crystal defects; Crystal growth; Crystal structure; EXAFS; Ferroelectric materials; Ferroelectrics; Nickel; Point defects; Single crystals; Strontium barium niobate; Structural analysis; Synchrotron radiation; Vacancy formation; X-ray diffraction; Crystal growth; Ferroelectrics; Vacancy formation; Synchrotron radiation; EXAFS; Crystal structure
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.07.085

A structural features, real compositions, and point defects of nominally pure and Cr- and Ni-doped Sr0.61Ba0.39Nb2O6 (SBN) crystals, which structure contains four chemically-different and ten crystallochemically-different atoms, have been determined using neutron, X-ray single crystal, X-ray powder, and X-ray synchrotron diffraction techniques, and EXAFS/XANES spectroscopy. The location of transition metal ions has been identified based on the analysis of electron (nuclear) density and confirmed by the EXAFS/XANES together with the definition of formal charges of Ni atoms in Ni-doped SBN crystals. The scope and application possibilities of diffraction methods and EXAFS/XANES spectroscopy for the determination of structural features and defect formation in functional bulk nominally-pure and Cr- and Ni-doped Sr0.61Ba0.39Nb2O6 single crystals is established.
•Undoped SBN, SBN:Cr, and SBN:Ni crystals were grown by the Stepanov technique.•Crystal structure was refined by X-ray, neutron diffraction, synchrotron radiation.•The real compositions, point defects, and location of impurities were refined.•The presence of Ni2+ and Ni3+ ions in the vicinity of Nb1 site was found by EXAFS.•The limits of applicability of methods and techniques were determined.