A. C. Impedance Analysis on b-axis Oriented Ba1-xSrxTi2O5 Prepared by an Arc-Melting Method

Stabilization of metastable ferroelectric Ba1−xCaxTi2O5 by breaking Ca-site selectivity via crystallization from glass

“…Whether it is a stable or metastable phase, it is noted that ferroelectric Ba 1− x Ca x Ti 2 O 5 was obtained up to x = 0.30 by crystallization from glass. This value is much higher than that reported for other substituted systems910. Considering that Sr, as compared with Ca, can easily substitute for Ba, because the ionic radius of Sr 2+ is closer to that of Ba 2+ than that of Ca 2+ , the larger substitution of Ca compared to Sr seems illogical.…”

“…On the other hand, few reports exist about the effects of substitution on BaTi 2 O 5 . Ba 1− x Sr x Ti 2 O 5 (0 ≤ x ≤ 0.12) prepared by arc-melting exhibited a slight decrease in T C 9. KF-doped BaTi 2 O 5 synthesized by spark plasma sintering exhibited ferroelectric relaxor behavior10.…”

Dielectric Properties of Ba<SUB>1&minus;<I>x</I></SUB>Ca<I><SUB>x</SUB></I>Ti<SUB>2</SUB>O<SUB>5</SUB> Prepared by Arc Melting

“…The " max was 2780 at x ¼ 0 and increased with increasing x, showing the highest value of 4950 at x ¼ 0:02. Comparing to the " max at x ¼ 0 in the previous study (1800), 9) the " max value in the present study was increased by modifying the mixing time of powders and slightly elongating an arc-melting time to eliminate the secondary phases of BaTiO 3 and Ba 6 Ti 17 O 40 and to improve the b-axis orientation. The T c of BCT 2 decreased from 750 K at = 0 to 665 K with increasing x up to 0.10.…”

“…9,17) It is known that the perovskite structure accommodates a large number of foreign elements. 18) However, BT 2 has a lower symmetry structure than BT, which consists of a combination of corner-and edge-shared TiO 6 octahedrons.…”

“…We have studied the effects of several foreignelement substitutions, e.g., Sr and Zr, on the dielectric properties of polycrystalline BT 2 prepared by arc melting. 9,10) It has long been known that the substitution of Ca in BT is effective to modify the dielectric properties. Mitsui et al 11,12) reported that the T c of BT increased from 403.8 to 409.2 K with increasing Ca substitution until x ¼ 0:08 in Ba 1Àx Ca xTiO 3 (BCT).…”