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Electric Relaxation Studies of Defects and Defect Associates in Dilute Ceria‐Lanthanum Oxide Solid Solutions
Author(s) -
Sarkar Partho,
Nicholson Patrick S.
Publication year - 1989
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1989.tb07672.x
Subject(s) - lanthanum , electric field , isothermal process , relaxation (psychology) , enthalpy , lanthanum oxide , solid solution , materials science , chemistry , analytical chemistry (journal) , oxide , thermodynamics , inorganic chemistry , metallurgy , social psychology , psychology , physics , chromatography , quantum mechanics
Electric modulus formalism was used to study relaxation processes in the 0.75‐mol%‐La 2 O 3 ‐doped CeO 2 system between 387 and 470 K in the frequency range 5 to 10 7 Hz. Two relaxation processes were observed in the isothermal studies: one at low frequencies due to long‐range migration of free oxygen vacancies (process A) and one at high frequencies due to charge reorientation relaxation of (La Ce V o ’defect associates (process B). The relaxation processes were analyzed using a nonexponential decay function (φ(t) = exp[—(t/τ o β] for 0<β1) of the electric field. The activation enthalpy estimated for process A is 0.72 eV and for process B is 0.55 eV.