TY - JOUR
T1 - Correlation between crystal and transport properties in LnBa 0.5Sr0.5Co1.5Fe0.5O 5 + δ (Ln - Selected lanthanides, Y)
AU - Świerczek, Konrad
AU - Yoshikura, Naoya
AU - Zheng, Kun
AU - Klimkowicz, Alicja
N1 - Funding Information:
The project was funded by the National Science Centre Poland (NCN) on the basis of the decision number DEC-2012/05/E/ST5/03772 .
PY - 2014/9/1
Y1 - 2014/9/1
N2 - Selected LnBa0.5Sr0.5Co1.5Fe 0.5O5 + δ (Ln - Pr, Nd, Sm, Gd and Y) oxides were studied in terms of their phase composition, formation of cation-ordered crystal structure, oxygen nonstoichiometry and transport properties. Despite partial substitution of bigger Ba2 + by smaller Sr2 + cations, A-site (Ln-Ba,Sr) cation ordering in LnBa0.5Sr0.5Co 1.5Fe0.5O5 + δ is preserved, but only for smaller Ln cations (Y3 +, Gd3 +). In the case of SmBa0.5Sr0.5Co1.5Fe0.5O 5 + δ, the synthesis procedure yielded material partially ordered, while for Pr3 + and Nd3 + cations XRD measurements indicated formation of cation-disordered samples. Oxygen content in the disordered materials is close to stoichiometric one (δ ≈ 1) at room temperature, while for cation-ordered samples δ < 1. Thermogravimetric measurements indicated that above 250 °C a decrease of mass occurs for all of the studied materials. Except for Y-containing sample, larger mass loss at 800 °C occurs for materials with heavier Ln element. The ordered materials show higher activation energy of the electrical conductivity in 25-300 °C temperature range, as well as different temperature dependence of Seebeck coefficient, comparing to the disordered ones. The highest electrical conductivity was measured for PrBa0.5Sr0.5Co 1.5Fe0.5O5 + δ. For this compound the ionic conductivity at 800 °C was determined to be of the order of 0.03 S cm- 1.
AB - Selected LnBa0.5Sr0.5Co1.5Fe 0.5O5 + δ (Ln - Pr, Nd, Sm, Gd and Y) oxides were studied in terms of their phase composition, formation of cation-ordered crystal structure, oxygen nonstoichiometry and transport properties. Despite partial substitution of bigger Ba2 + by smaller Sr2 + cations, A-site (Ln-Ba,Sr) cation ordering in LnBa0.5Sr0.5Co 1.5Fe0.5O5 + δ is preserved, but only for smaller Ln cations (Y3 +, Gd3 +). In the case of SmBa0.5Sr0.5Co1.5Fe0.5O 5 + δ, the synthesis procedure yielded material partially ordered, while for Pr3 + and Nd3 + cations XRD measurements indicated formation of cation-disordered samples. Oxygen content in the disordered materials is close to stoichiometric one (δ ≈ 1) at room temperature, while for cation-ordered samples δ < 1. Thermogravimetric measurements indicated that above 250 °C a decrease of mass occurs for all of the studied materials. Except for Y-containing sample, larger mass loss at 800 °C occurs for materials with heavier Ln element. The ordered materials show higher activation energy of the electrical conductivity in 25-300 °C temperature range, as well as different temperature dependence of Seebeck coefficient, comparing to the disordered ones. The highest electrical conductivity was measured for PrBa0.5Sr0.5Co 1.5Fe0.5O5 + δ. For this compound the ionic conductivity at 800 °C was determined to be of the order of 0.03 S cm- 1.
KW - Cation ordering in perovskites
KW - Crystal structure
KW - Mixed conductivity
KW - Oxygen nonstoichiometry
KW - Transport properties
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U2 - 10.1016/j.ssi.2013.10.058
DO - 10.1016/j.ssi.2013.10.058
M3 - Article
AN - SCOPUS:84903173168
VL - 262
SP - 645
EP - 649
JO - Solid State Ionics
JF - Solid State Ionics
SN - 0167-2738
ER -