Mobility determinations from weight measurements in solid solutions of (Ba, Sr) TiO3

Abstract

Ba1–xSrxTiO3 ceramics and SrTiO3 single crystals subjected to reducing treatment show‐weight losses due to the release of oxygen. In parallel the reduction causes an electrical conductivity which is proportional to the weight loss. On the justified assumption that oxygen vacancies occur during the reduction process and that each vacancy loses an electron to the conduction band at room temperature, it is possible to determine from the weight‐loss measurements the number of electrons and, in combination with the electrical conductivity, their mobility. The mobility thus determined is 0.6 cm2/Vs for BaTiO3, rising with increasing Sr concentration to 5.9 cm2/Vs for SrTiO3. These gravimetrically determined mobilities are in satisfactory agreement with those found from Hall‐effect and thermo‐electric power measurements.

Electronic transport properties of Sr1−xLaxTiO3 ceramics

“…There the oxygen vacancies are singly ionized. [17][18][19] Since it is well known that extrinsic donors are exhausted at 77 K ͑Ref. 16͒ and even at 4.2 K, 20 Eq.…”

Structural and Dielectric Properties of La0.33Sr0.67M0.33Ti0.67O3±δ (M = Mn or Fe) Perovskites

“…The electrons released in this reaction may be captured by Fe 3+ ions to form Fe 2+ ions. At lower temperatures, <675 K, the oxygen vacancies become singly ionized, V • o [24][25][26][27]. The change in ionization can be written as…”

Oxygen Vacancies in Perovskite Oxide Piezoelectrics

“…For both stoichiometric and oxygen-deficient samples, the n -type (electronic) conductivity only was found. Conductivity by hopping of small electron polarons was established in stoichiometric ferroelectrics [ 17 , 18 , 19 , 20 , 21 ]. Additionally, electronic band conductivity (i.e., by electrons in the conduction band) was detected for oxygen-deficient samples and/or at high temperatures [ 22 , 23 , 24 ].…”

“…Additionally, electronic band conductivity (i.e., by electrons in the conduction band) was detected for oxygen-deficient samples and/or at high temperatures [ 22 , 23 , 24 ]. Remarkably, although the electron hopping transport [ 17 ] is known for a long time as the chemical experiment is [ 1 ], this transport is nearly never considered in studies of ferroelectric piezoelectrics. Despite the experimental physical evidence of the n -type conductivity, the concept of oxygen vacancies as mobile charge carriers is unhesitatingly applied to diverse aspects of ferroelectric behavior.…”