title: Dopant positions in strontium/chromium- and barium-doped KTP, determined with synchrotron X-radiation
abstract: Structure factors for strontium/chromium- (Sr/Cr) and barium- (Ba) doped potassium titanyl phosphate (KTiOPO(4), KTP) were measured with focused synchrotron X-radiation [0.75000 (9) A] using a fast avalanche photodiode counter. Space group Pna2(1), Z = 8, a = 12.786 (2), b = 6.3927 (8), c = 10.5585 (9) A, T = 293 (1) K, R = 0.028 (SrCrKTP); a = 12.851 (6), b = 6.418 (3), c = 10.620 (5) A, T = 120 (1) K, R = 0.031 (BaKTP). The refinement of the dopant positions showed that Ba(2+) is positioned in the larger of the two K cavities of KTP, while the smaller Sr(2+) ion is located in both. Split positions are found for the strontium dopant in both cavities and they are located in the positive c direction from the potassium cation. The chromium dopant has two different oxidation states, namely +III and +VI; in both states the dopant is located inside the TiO(6) octahedra. The two structures show slightly less distorted TiO(6) octahedra than pure KTP.
authors: Inorganic Chemistry, Chalmers University of Technology, SE-412 96 Goteborg, Sweden. stn@inoc.chalmers.se.
authors: ST
authors: Norberg
authors: VA
authors: Streltsov
authors: G
authors: Svensson
authors: J
authors: Albertsson