Microwave dielectric properties of LaScO3-TiO2 materials

Do Kyun Kwon, Michael T. Lanagan, Thomas R. Shrout

Research output: Contribution to journalConference article

Abstract

From fundamental ionic polarizability concepts, LaScO3 was projected as a candidate dielectric material for microwave application. The microwave dielectric properties of LaScO3 were obtained as the dielectric permittivity of 24, Qxf of 18,000 GHz, with a temperature coefficient of resonant frequency (TCP) of -69 ppm/°C. Solid solutions and polyphase assemblages were investigated in the LaScO3-TiO2 system as a function of TiO2 content, and correlated with the microwave dielectric properties. Orthorhombic perovskite LaScO3 transformed to tetragonal symmetry with Ti substitution on the B-site of LaScO3 owing to the ionic radius difference between Sc3+ and Ti 4+. With this phase transition, the formation of A-site vacancies (VLa‴) resulted in the precipitation of a La deficient secondary phase. The substitution of Ti also affected the dielectric properties. The dielectric constant increased and TCF became less negative with increased TiO2 addition. However, the Qxf value decreased, due to the formation of the secondary phase. For the case of the 0.6LaScO3-0.4TiO 2 composition, a dielectric K of 40, Qxf of 6,000 GHz and nearly zero TCF were obtained.

Original languageEnglish (US)
Pages (from-to)59-64
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume783
DOIs
StatePublished - Jan 1 2003
EventMaterials, Integration and Packaging Issues for High - Frequency Devices - Boston, MA, United States
Duration: Dec 1 2003Dec 3 2003

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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