Ceramic ferroelectric composite materials with enhanced electronic properties BSTO-Mg based compound-rare earth oxide

US6074971A · kind A · utility

Assignee

• The United States of America as represented by the Secretary of the Army · US

Inventors

• Luna H. Chiu · Edgewood, US
• Louise Sengupta · Ellicott City, US
• Steven Stowell · Columbia, US
• Somnath Sengupta · Ellicott City, US
• Jennifer Synowczynski · Joppatowne, US

Key dates

• Filing date: Nov 13, 1998
• Grant date: Jun 13, 2000
• Expiry date: Nov 13, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B35/465
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Ceramic ferroelectric composite materials comprising barium strontium titte/magnesium and oxygen-containing compound composite further doped with rare earth (lanthanide) oxides. More particularly, these inventive composites are comprised of Ba.sub.1-x Sr.sub.x TiO.sub.3 /Mg--O based compound/rare earth oxide composite, wherein x is greater than or equal to 0.0 but less than or equal to 1.0, and wherein the weight ratio of BSTO to Mg compound may range from 99.75-20 wt. % BSTO to 0.25-80 wt. % Mg compound, and wherein said rare earth oxide additive comprises less than about 10 mole percent of the composite. The rare earth oxides of the composite include all oxides of the lanthanide series elements including scandium and yttrium, as well as combinations thereof. The magnesium-based compound may be selected from the group consisting of MgO, MgZrO.sub.3, MgZrSrTiO.sub.3, MgTiO.sub.3, and MgCO.sub.3. This new class of composite materials has enhanced electronic properties including: low dielectric constants; substantially decreased electronic loss (low loss tangents); increased tunability; increased temperature stability; decreased sintering temperatures; and low curie temperatures. The…