Open AccessSynchrotron X‐ray Imaging of the Electron Density in R FeO 3 ( R = Y, Ho) Using an APD Detector
Author(s) -
Streltsov Victor A.,
Ishizawa Nobuo,
Kishimoto Shunji
Publication year - 1998
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049598001447
Subject(s) - synchrotron , physics , electron , x ray , detector , nuclear physics , materials science , optics
Structure factors for small hydrothermally grown yttrium and holmium orthoferrites, R FeO 3 ( R = Y, Ho), were measured with focused synchrotron radiation at wavelengths of 0.70 and 0.84 Å using both scintillation and high‐speed avalanche photodiode (APD) detectors. Resulting APD Δρ images showed striking correlations between aspherical electron densities around Fe and rare‐earth metals. Approximate high symmetry in the Δρ images indicates that cations deform the electron density far more strongly than the O atoms. The Ho—Fe magnetic interactions appear to affect the electron density distribution of the Fe atoms and the magnetic phase transitions. Space group Pnma , orthorhombic, YFeO 3 (APD): M r = 192.76, a = 5.5931 (3), b = 7.6102 (4), c = 5.2806 (3) Å, V = 224.77 (2) Å 3 , Z = 4, D x = 5.695 Mg m −3 , μ 0.84 = 15.56 mm −1 , F (000) = 356, T = 293 K, R = 0.045, wR = 0.073, S = 4.83 (9) for 1282 unique reflections; HoFeO 3 (APD): M r = 268.78, a = 5.5922 (3), b = 7.6157 (5), c = 5.2798 (3) Å, V = 224.86 (2) Å 3 , Z = 4, D x = 7.939 Mg m −3 , μ 0.84 = 61.98 mm −1 , F (000) = 356, T = 293 K, R = 0.036, wR = 0.037, S = 3.07 (6) for 1284 unique reflections.