Microwave characteristics of A(B sup 3 sub 1/2 B sup 5 sub 1/2 )O sub 3 ceramics; A = Ba, Ca, Sr; B sup 3 + = La, Nd, Sm, Yb; B sub 5 + = Nb, Ta

Journal Article · Sun Oct 01 04:00:00 EDT 1989 · Journal of the American Ceramic Society; (USA)

DOI:https://doi.org/10.1111/j.1151-2916.1989.tb06006.x· OSTI ID:7122420

Takata, M; Kaheyama, K ^[1]

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1. Sumitomo Special Metals Co. Ltd., Osaka (Japan)

This paper reports the dielectric properties of A(B{sub 1/2}{sup 3 +}B{sub 1/2}{sup 5 +})O{sub 3} (A = Ba, Ca, Sr; B{sup 3 +} = La, Nd, Sm, Yb; B{sup 5 +} = Nb, Ta) ceramics investigated at microwave frequencies. Sr(B{sub 1/2}{sup 3 +}B{sub 1/2}{sup 5 +})O{sub 3} and Ca(B{sub 1/2}{sup 3 +}B{sub 1/2}{sup 5 +})O{sub 3} ceramics have relative dielectric constants ({epsilon}{sub r}) above 20 and negative temperature coefficients of resonant frequency ({tau}{sub f}). In the group of Ba(B{sub 1/2}{sup 3 +}B{sub 1/2}{sup 5 +})O{sub 3} ceramics, {tau}{sub f} changes from +118 ppm/{degrees}C to nearly zero according to the kinds of B-site ions. Among the ceramics investigated, Sr(SM{sub 1/2}Ta{sub 1/2})O{sub 3} ceramics have the highest Q values at microwave frequencies. For Sr(Sm{sub 1/2}Ta{sub 1/2})O{sub 3} ceramics Q = 7000, {epsilon}{sub r} = 27.7, and {tau}{sub f} = -62.5 ppm/{degrees}C at 8.5 GHz. The microstructure of Sr(SM{sub 1/2}Ta{sub 1/2})O{sub 3} ceramics is composed of a matrix of the ternary compound (Sr-Sm-Ta-O system) and secondary phase grains of the binary compound (Sm-Ta-O system).

• OSTI ID: 7122420
• Journal Information: Journal of the American Ceramic Society; (USA), Journal Name: Journal of the American Ceramic Society; (USA) Vol. 72:10; ISSN JACTA; ISSN 0002-7820
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE
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