TY - JOUR
T1 - Effects of substitution of Ti4+ by Nb5+ on the electrical properties of BaTi2O5 prepared by a floating zone method
AU - Shiga, Keiji
AU - Katsui, Hirokazu
AU - Kakuda, Hiroyuki
AU - Yoshikawa, Kazuma
AU - Tsuneyoshi, Jun
AU - Goto, Takashi
N1 - Funding Information:
We thank Prof. T. Tsurumi and Prof. H. Takeda (Tokyo Institute of Technology, Japan) for their kind help to measure the ferroelectric hysteresis loops. This study was supported by a Grant-in-Aid of Tohoku University Division for International Advanced Research and Education. This study was also partially supported by Seiko Instruments Inc.
Publisher Copyright:
© 2016 Elsevier Ltd and Techna Group S.r.l.
PY - 2016/11/15
Y1 - 2016/11/15
N2 - Nb5+-substituted single-crystalline BaTi2O5 (Ba(Ti1−xNbx)2O5+z) was synthesised by a floating zone method, and the effect of Nb5+ substitution on the dielectric properties of Ba(Ti1−xNbx)2O5+z was investigated. The growth direction of Ba(Ti1−xNbx)2O5+z was parallel to the b axis. The a lattice constant and β angle increased from 1.6906 to 1.6918 nm and from 103.09° to 103.13° at x=0–0.7 at%, respectively. With increasing x, the Curie temperature of Ba(Ti1−xNbx)2O5+z decreased from 750 to 652 K. A complex impedance plane plot of BaTi2O5 at 598 K in the b direction showed a semicircle at high frequencies and a spike inclined at 45° to the real axis at low frequencies, indicating ionic conduction of bulk BaTi2O5. At x>0.002 (0.2 at%), the complex impedance plots of Ba(Ti1−xNbx)2O5+z showed no inclined spike, suggesting dominantly electronic conduction. The electrical conductivity of Ba(Ti1−xNbx)2O5+z increased with temperature with an activation energy of 1.4 to 1.7 eV and was minimum at x=0.001 (0.1 at%). The spontaneous polarisation of Ba(Ti0.998Nb0.002)2O5+z was 2.7×10−2 C m−2, which was 2.5 times higher than that of BaTi2O5.
AB - Nb5+-substituted single-crystalline BaTi2O5 (Ba(Ti1−xNbx)2O5+z) was synthesised by a floating zone method, and the effect of Nb5+ substitution on the dielectric properties of Ba(Ti1−xNbx)2O5+z was investigated. The growth direction of Ba(Ti1−xNbx)2O5+z was parallel to the b axis. The a lattice constant and β angle increased from 1.6906 to 1.6918 nm and from 103.09° to 103.13° at x=0–0.7 at%, respectively. With increasing x, the Curie temperature of Ba(Ti1−xNbx)2O5+z decreased from 750 to 652 K. A complex impedance plane plot of BaTi2O5 at 598 K in the b direction showed a semicircle at high frequencies and a spike inclined at 45° to the real axis at low frequencies, indicating ionic conduction of bulk BaTi2O5. At x>0.002 (0.2 at%), the complex impedance plots of Ba(Ti1−xNbx)2O5+z showed no inclined spike, suggesting dominantly electronic conduction. The electrical conductivity of Ba(Ti1−xNbx)2O5+z increased with temperature with an activation energy of 1.4 to 1.7 eV and was minimum at x=0.001 (0.1 at%). The spontaneous polarisation of Ba(Ti0.998Nb0.002)2O5+z was 2.7×10−2 C m−2, which was 2.5 times higher than that of BaTi2O5.
KW - BaTiO
KW - Floating zone method
KW - Impedance
KW - Ionic conduction
KW - Single crystal
UR - http://www.scopus.com/inward/record.url?scp=85028236826&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85028236826&partnerID=8YFLogxK
U2 - 10.1016/j.ceramint.2016.08.023
DO - 10.1016/j.ceramint.2016.08.023
M3 - Article
AN - SCOPUS:85028236826
VL - 42
SP - 17283
EP - 17289
JO - Ceramics International
JF - Ceramics International
SN - 0272-8842
IS - 15
ER -