Chemical reactions and dielectric properties of the BaTiO{sub 3}-LaAlO{sub 3} and BaTiO{sub 3}-LaAlO{sub 3}-LaTi{sub 3/4}O{sub 3} systems

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1996.7221· OSTI ID:569202

Skapin, S; Kolar, D; Suvorov, D ^[1]

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1. Univ. of Ljublijana (Slovenia)

BaTiO{sub 3}=LaAlO{sub 3} interaction at high temperatures results in formation of (Ba,La)(Ti,Al)O{sub 3} solid solution, BaAl{sub 2}O{sub 4}, and Ba{sub 2}TiO{sub 4}. The composition of solid solution can be expressed as Ba{sub 1-n}La{sub n}Ti{sub 1-0.52n}Al{sub 0.36n}O{sub 3} with 0 {le} n {le} 0.27. Formation of secondary phases BaAl{sub 2}O{sub 4} and Ba{sub 2}TiO{sub 4} which form due to unequal solubility of La{sup 3+} and Al{sup 3+} ions into the perovskite BaTiO{sub 3} lattice can be prevented by the addition of La{sub 2}O{sub 3} and TiO{sub 2} in ratio 2:3, i.e., as LaTi{sub 3/4}O{sub 4}. Incorporation of La and Al into BaTiO{sub 3} strongly decreases the Curie temperature of BaTiO{sub 3}, {approx} 35 K/mol % LaAlO{sub 3} added. (Ba,La)(Ti,Al)O{sub 3} solid solution ceramics exhibit relatively low permittivities at room temperature (734-129) and very low dielectric losses, tan {delta}<5x10{sup {minus}4} measured at 1 MHz. The temperature stability of permittivity increases with LaTi{sub 3/4}O{sub 3} as well with LaAlO{sub 3} concentration.

• OSTI ID: 569202
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 129; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
BARIUM COMPOUNDS
CERAMICS
DIELECTRIC PROPERTIES
LANTHANUM OXIDES
PERMITTIVITY
PEROVSKITE
TITANATES