Ba (Mg<inf>1/3</inf>Ta<inf>2/3</inf>)O<inf>3</inf>Ceramics with Ultra-Low Loss at Microwave Frequencies

Abstract

h i m u r a C e n t r a l R e s e a r c h L a b o r a t o r y o f Sumitomo M e t a l Mlning C o . , L t d . Nakakokubun 3-18-5, I c h ikava-Shl. Ch i b a 272. J a p a n * P r e s e n t A d d r e s s D e p a r t m e n t of M e t a l l u r g y and M a t e r i a l s E n g i n e e r i n g , L e h i g h U n l v e r s l t y . B e t h l e h e m , PA 18015. U.S.A. Abstract An a p p l i c a t i o n o f a f a s t h e a t i n g p r o c e s s a t t a i n s a r e m a r k a b l y h i g h Q v a l u e of t h e p u r e BMT (Ba(Mg1/3Ta2,3)03) c e r a m i c s . Q v a l u e s t r o n g l y d e p e n d s on t h e o r d e r i n g of t h e B s i t e i o n s and t h e d e n s l t y of t h e c e r a m i c s b u t n o t on t h e g r a i n s i z e . I t is found t h a t t h e The maximum Q v a l u e i s o b t a i n e d f o r t h e h i g h d e n s i t y a n d h l g h o r d e r , which a t t a i n s more t h a n 35000 a t 10CHz. I . I n t r o d u c t i o n R e c e n t l y complex p e r o v r k i t e compounds v i t h the g e n e r a l f o r m u l a A<B ' B . 10 (A=Ba, S r , B'=Zn, Mg, CO, N I , B'=Ta, Nb) h a v e b e e n found t o be good d i e l e c t r i c m a t e r i a l s f o r mlcrowave r e s o n a t o r . T h e s e compounds h a v e h i g h d i e l e c t r i c c o n s t a n t s Cr (20-401, h i g h d i e l e c t r i c loss q u a l i t y R (some a r e o v e r 10000) and s m a l l t e m p e r a t u r e c o e f f i c i e n t of t h e r e s o n a n t f r e q u e n c y If. A s t h e f r e q u e n c i e s u s e d In c o m m u n i c a t i o n s y s t e m become h i g h e r , s t i l l h i g h e r Q m a t e r i a l s a r e n e c e s s a r y . 113 2/3 3 Some p a p e r s h a v e b e e n r e p o r t e d (1-41 on t h e mechanism of t h e d i e l e c t r i c loss in t h e complex p e r o v s k i t e compounds. Nomura e t a l . (11 r e p o r t e d t h a t v e l l d e n s e Ba(Mgl/RTa2,3)03 (BMT) s i n t e r e d w i t h a s m a l l amount o f Mn as sintering aid had [r=25 and R=16800 a t 10. SCHz. T h i s P v a l u e h a s been t h e h i g h e s t among t h e complex p e r o v s k i t e compounds. Kawashima e t a l . (21 r e p o r t e d t h a t 0 was improved v i t h i n c r e a s i n g t h e o r d e r i n g o f Zn and Ta i n B s i t e of Ba(Znl/3Ta2/3)03 (BZT). a c c o r d i n g t o Desu and O'Bryan (31, c o n t r o l of v o l a t i l e compound ZnO o f BZT was i m p o r t a n t i n c o n t r o l l i n g 8 . While Based on t h e c l a s s i c a l d i e l e c t r i c d i s p e r s i o n t h e o r y , t h e l o s s t a n g e n t t a n 6 is a p p r o x i m a t e l y p r o p o r t i o n a l t o t h e damping c o n s t a n t . The damping c o n s t a n t i s e x p l a i n e d ( 5 ) due t o t h e l a t t i c e anharmon i c i n t e r a c t i o n and a Is0 t h e l a t t i c e i m p e r f e c t i o n , e . g . , i m p u r i t i e s , d i s l o c a t i o n s , l o c a l s t r a i n s , e t c . Wakino e t a l . (41 i n v e s t i g a t e d t h e l a t t i c e v i b r a t i o n s of BZT and B a ( Z r , Zn, Ta)Oj s o l i d s o l u t i o n s u s i n g FT-IR s p e c...

Microwave Dielectrics Based on Complex Oxide Systems

“…Therefore, Nomura with coauthors [98] proposed to prepare dense ceramics ( ≈ 7520 kg/m 3 ) by using additionally manganese impurities. Matsumoto and Hinga [99] used fast heating (330 0 C/min) for the same purposes, which made it possible to achieve 96% of the theoretical density. To increase the rate of sintering and to order ions in the B sublattice, the authors of [100,101] proposed preliminarily synthesized MTa2O6(M = Mg, Zn) as starting reagents.…”

Dielectric properties of MgB2O6 (B5+=Nb, Ta, Sb) at microwave frequencies

“…Up until now, these dielectric materials are usually obtained from the complex perovskite compounds and their solid solutions such as Ba(Zn1/3Ta2/3)O3 and Ba(Mg1/3Ta2/3)O3. 1), 2) However the elaborated sintering processes such as high sintering temperature above 1400°C and long sintering time are required to achieve sufficiently high sintered density for the industrial applications of the complex perovskite compounds.…”

Properties of Ba(Mg1/3Ta2/3)O3 thin films prepared by metalorganic solution deposition technique for microwave applications

“…[2][3][4] In particular, Ba͑Mg 1/3 Ta 2/3 ͒O 3 ͑BMT͒ has been reported to show a dielectric constant ⑀ r of 25, Q value of 36 000 at 10 GHz, and a low temperature coefficient of resonant frequency of 4.4 ppm/°C. [5][6][7] However, poor sinterability and high densification temperature are the major problems to be solved to exploit the excellent properties of bulk BMT ceramics in microwave devices. The bulk ceramics prepared by conventional solid state reaction method with addition of various sintering aids require extremely high sintering temperature ͑у1600°C͒ or very long sintering time at lower temperatures ͑ϳ100 h at 1450°C͒.…”

“…Attempts have also been made to reduce the processing temperature by using modified solid state reaction method, rapid heating, and solgel method. [4][5][6][7][8][9] A reduction in sintering temperature of BMT is necessary for use as a dielectric resonator in miniaturized communication devices. In the present work, we have fabricated the thin films of Ba͑Mg 1/3 Ta 2/3 ͒O 3 for applications in microwave frequency communications devices.…”

“…The dielectric constant of thin films was comparable to the value (⑀ r ϳ23.5-25) reported for bulk BMT ceramics. [5][6][7][8][9]12 The intrinsic dissipation factor value is expected to be even lower than 0.009 as the effects of series and parallel resistances due to measurement configuration on the measured values of capacitance and loss factor were not modeled. The dielectric properties did not show any appreciable dispersion with frequency up to about 1 MHz indicating good film/electrode interfacial characteristics.…”