Effect of crystal orientation on the segregation of aliovalent dopants at the surface of La0.6Sr0.4CoO3

Pişkin, Fatih
Bliem, Roland
Yildiz, Bilge
The effect of crystal orientation on aliovalent dopant segregation at the surface of La0.6Sr0.4CoO3 as a model perovskite oxide was investigated. La0.6Sr0.4CoO3 pellets were produced and then annealed in air at 800 degrees C for 2-5 hours to drive the cation segregation at the surface. To quantify the chemical state of the pellets' surface, including cation composition and secondary phase precipitates rich in Sr, the pellets were characterized by X-ray photoelectron spectroscopy and Auger electron spectroscopy. To systematically assess the correlation between crystal orientation and dopant cation segregation, selected regions at the surface of the annealed pellets were analyzed by scanning electron microscopy and electron backscatter diffraction. Investigation of more than 300 grains revealed that the area coverage of the Sr-rich precipitates on grains having a {001} orientation was more than 3 times higher compared to that on the {101} and {111} orientations. On the other hand, the number density of precipitates was very similar on each grain orientation. This grain orientation dependent behavior indicates that the exposed facet plays an important role in dopant cation segregation, especially in the growth of secondary phases, likely by altering the surface energy and charged defect concentration. The present study provides insights into the importance of atomic arrangements in determining the surface stability and cation segregation tendency on perovskite oxides.


Hasanlı, Nızamı; MELNIK, NN (1984-01-01)
An experimental study has been carried out to investigate Raman scattering spectra of GaS1-xSex solid solutions in which a one-dimensional localization of interlayer mode due to a disorder in the layer stacking was observed.
Effect of Illumination Temperature on Thermally Stimulated Current Spectrum of TlInS2
Özdemir, Salahattin; Bucurgat, Mahmut; Bulur, Enver (1999-01-01)
The effect of pre-illumination on both thermally stimulated current and photocurrent spectra of TlInS2 crystal is investigated. The increase in the photosensitivity of the crystal by several orders of magnitude together with the appearance of a new peak in the thermally stimulated current spectrum are observed as a result of the pre-illumination process. The filling of the traps, especially the sensitizing centers, during the pre-illumination is found to be the most favourable physical mechanism to explain ...
Effects of gold-induced crystallization process on the structural and electrical properties of germanium thin films
Kabacelik, Ismail; Kulakci, Mustafa; Turan, Raşit; ÜNAL, NURİ (Wiley, 2018-07-01)
Gold-induced (Au-) crystallization of amorphous germanium (-Ge) thin films was investigated by depositing Ge on aluminum-doped zinc oxide and glass substrates through electron beam evaporation at room temperature. The influence of the postannealing temperatures on the structural properties of the Ge thin films was investigated by employing Raman spectra, X-ray diffraction, and scanning electron microscopy. The Raman and X-ray diffraction results indicated that the Au-induced crystallization of the Ge films ...
Effect of operating parameters on selective separation of heavy metals from binary mixtures via polymer enhanced ultrafiltration
Muslehiddinoglu, J; Uludağ, Yusuf; Ozbelge, HO; Yılmaz, Levent (Elsevier BV, 1998-03-18)
Performance of continuous polymer enhanced ultrafiltration (PEUF) method was investigated for removal of mercury and cadmium from binary mixtures. This method includes the addition of polyethyleneimine (PEI) as a water soluble polymer to bind the metals, which was followed by ultrafiltration operation performed on both laboratory and pilot scale systems. The influence of various operating parameters such as temperature, metal/polymer ratio, presence of calcium ions and pH on retention of metals and permeate...
Effect of swaging on microstructure and tensile properties of W-Ni-Fe alloys
DURLU, NURİ; Caliskan, N. Kaan; Bor, Sakir (Elsevier BV, 2014-01-01)
The objective of this study was to investigate the effect of swaging on the microstructure and tensile properties of high density two phase alloys 90W-7Ni-3Fe and 93W-4.9Ni-2.1Fe. Samples were liquid phase sintered under hydrogen and argon at 1480 degrees C for 30 min and then 15% cold rotary swaged. Measurement of microstructural parameters in the sintered and swaged samples showed that swaging slightly increased tungsten grain size in the longitudinal direction and slightly decreased tungsten grain size i...
Citation Formats
F. Pişkin, R. Bliem, and B. Yildiz, “Effect of crystal orientation on the segregation of aliovalent dopants at the surface of La0.6Sr0.4CoO3,” JOURNAL OF MATERIALS CHEMISTRY A, pp. 14136–14145, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/51516.