NaNbO3–BaTiO3–Ba0.93Ca0.07TiO3 ceramic composites for temperature stable X8R rated dielectrics

J James H. Killeen (School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,) J Julian S. Dean (School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,) S Stuart Creasey-Gray (School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,) D Derek C. Sinclair (School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,)

Abstract

X7R rated dielectrics with room temperature relative permittivity (εr) of ∼2000 are produced as ceramic–ceramic composites based on a ferroelectric BaTiO3 matrix (BT, Curie Temperature, Tc = 122 °C) and a relaxor-ferroelectric Na0.6Ba0.4Nb0.6Ti0.4O3 filler (Tmax = −135 °C at 250 kHz) in a respective 80:20 wt. % mass fraction. X8R rating is achieved when the composite is formed with a Ba0.93Ca0.07TiO3 (BCT, Tc = 129 °C) matrix phase instead of BT. The enhancement from X7R to X8R performance is attributed to creating a broader εr peak at ∼121 °C due to a wider distribution of A-site cations in the composite, as opposed to an increase in Tc of monolithic BCT.

Article Details

Volume / Issue Vol. 128, Issue 3
Published January 19, 2026
ISSN 0003-6951
Publisher American Institute of Physics

Journal Info

Applied Physics Letters

American Institute of Physics

ISSN: 0003-6951 Physical Sciences

Authors (4)

J

James H. Killeen

School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,

J

Julian S. Dean

School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,

S

Stuart Creasey-Gray

School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,

D

Derek C. Sinclair

School of Chemical, Materials and Biological Engineering, Sir Robert Hadfield Building, University of Sheffield , Mappin Street, Sheffield S1 3JD,