TY - JOUR
AU1 - Medarde, M.
AU2 - Rodríguez-Carvajal, J.
AB - The oxygen deficient and formally Ni1+-Ni2+ mixed-valence La2−x
SrxNiO4−δ
 system has been studied by means of neutron diffraction. It is found that, for the described synthesis procedure, there exists a critical Sr concentration x
c ≈ 0.135 separating the stability regions of two different crystallographic phases. For small Sr doping (x < x
c), La2−x
Sr
xNiO
4−δ samples have basically the same structure as stoichiometric La2NiO4, undergoing similar phase transitions. For x > x
c, the partial ordering of the oxygen vacancies produces a change of the crystallographic symmetry (from Bmab to Immm) and prevents the two structural phase transitions observed in the x < x
c region. In contrast to the behavior observed in hole-doped nickelates, the local fluctuations of the oxygen content produce lattice microstrains, the presence of which is clearly detected by the strong broadening of a family of Bragg reflections. A simple statistical model has been used to quantitatively characterize the microstrain distribution, supposed to be gaussian, from the observed (hkl) -dependence of the reflection broadening.
TI - Oxygen vacancy ordering in La2− x SrxNiO4 − δ (0 ≤ ≤ 0.5): the crystal structure and defects investigated by neutron diffraction
JF - Zeitschrift für Physik B Condensed Matter
DO - 10.1007/s002570050293
DA - 2014-02-21
UR - https://www.deepdyve.com/lp/springer-journals/oxygen-vacancy-ordering-in-la2-x-srxnio4-0-0-5-the-crystal-structure-2cEOq3pGD3
SP - 307
EP - 315
VL - 102
IS - 3
DP - DeepDyve
ER -