Growth, Dielectric and Pyroelectric Properties of 0.9Pb(Znl/3Nb2/3)O3-0.1PbTiO3Single Crystals
Growth, Dielectric and Pyroelectric Properties of 0.9Pb(Znl/3Nb2/3)O3-0.1PbTiO3Single Crystals
复制标题
0.9Pb(Znl/3Nb2/3)O3-0.1PbTiO3单晶的生长、介电和热电性能
DOI:
10.1109/isaf.1986.201187
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发表时间:
1986
期刊:
影响因子:
--
通讯作者:
L. Cross
中科院分区:
文献类型:
--
作者:
Z. Chang;A. Bhalla;L. Cross
S i n g 1 e c r y s t a l s o r ' 0 .9 PD ( Z n l I 3 N b 2 030 . 1 P b T i 0 3 were g r o w n u s i n g t h e f l u x m e t h o d . T h e d i e l e c t r i c p r o p e r t y a l o n g t h e p s e u d o c u b i c [I111 and [ l o 0 1 d i r e c t i o n s was m e a s u r e d as a f u n c t i o n of t e m p e r a t u r e and f r e q u e n c y . T h e e f f e c t s o f p o l i n g a n d D C b i a s f i e l d were i n v e s t i g a t e d . T h e p y r o e l e c t r i c p r o p e r t y a l o n g t h e s e two d i r e c t i o n s was a l s o measured. 1. I n t r o d u c t i o n The Pb(Znl, 3Nb2, )03-PbTi03 (PZN-PT) s y s ten is known t o n a v e a n e a r m o r p h o t r o p i c p h a s e b o u n d a r y b e t w e e n t h e t e t r a g o n a l and r h o m b o h e d r a l p h a s e i n t h e range o f 9 t o 9.5 mole% P b T i 0 3 . C r y s t a l s w i t h more t h a n 9.5% P b T i 0 3 s h o w t e t r a g o n a l s y m m e t r y , w h i l e t h o s e w i t h l e s s t h a n 94, P b T i 0 3 s h o w rhombohedral symmetry t l l . C r y s t a l s w i t h 9% PbTi03 were f o u n d t o h a v e v e r y l a r g e d i e l e c t r i c a n d p i e z o e l e c t r i c c o n s tan ts [ 2 I . I n t h i s p a p e r t h e g r o w t h and c h a r a c t e r i z a t i o n of c r y s t a l s w i t h s t a r t i n g c o m p o s i t i o n s 0.9PZN-O.1PT a r e d i s c u s s e d . T h e d i e l e c t r i c a n d p y r o e l e c t r i c p r o p e r t i e s a l o n g t h e p s e u d o c u b i c 1 1 1 1 1 a n d I 1 0 0 1 d i r e c t i o n s a n d t h e e f f e c t s of p o l i n g a n d DC b i a s f i e l d o n t h e d i e l e c t r i c b e h a v i o r a r e a l s o i n v e s t i g a t e d , 2 . C r y s t a l Growth S i n g 1 e c r y s t a l s 0 f 0. 9 P b ( Z n l 3 N b 2 1 030 . 1 P b T i 0 3 (PZNO.1PT) were g r o w n f r o m m o l t e n PbO f l u x by s l o w c o o l i n g . S t a r t i n g m a t e r i a l s were PbO. ZnO. N b 2 0 5 a n d T i 0 2 i n s t o i c h i o m e t r i c p r o p o r t i o n . A compound t o f l u x r a t i o o f 1 : 2 i n m o l e w a s u s e d . T h e c h a r g e was p l a c e d i n a p l a t i n u m c r u c i b l e a n d h e a t e d t o 1230°C. After a s o a k i n g p e r i o d o f 5 h r s , t h e c h a r g e was s l o w l y c o o l e d a t a r a t e of 3-SuC/hr t o 900°C a n d t h e n t o room t e m p e r a t u r e i n 2 4 h r s . T h e PbO t ' l u x w a s r e m o v e d by d i s s o l v i n g i n h o t a c e t i c a c i d . T h e c r y s t a l s o b t a i n e d a r e m o s t l y i n t h e form o f a n a r rowhead or i r r e g u l a r i n s h a p e w i t h a l i n e a r d i m e n s i o n of 1 t o 3 mm. and h a v e brown c o l o r . Some s m a l l e r c r y s t a l s a l s o s h o w r e c t a n g u l a r f a c e s a n d h a v e l i g h t e r c o l o r . Back r e f l e c t i o n Laue t e c h n i q u e r e v e a l s t h a t t h e p s e u d o c u b i c 1 1 1 1 1 d i r e c t i o n i s a l o n g t h e d i r e c t i o n o f t h e a r rowhead and t h e I1001 d i r e c t i o n is normal t o t h e r e c t a n g u l a r race. X-ray p o w d e r d i f f r a c t i o n p a t t e r n s do n o t i n d e x a s a s i n g 1 e p h a s e . I m p o s i n g a PhOmbOhedPal s y m m e t r y r e s u l t s i n t h e p a r a m e t e r s a = 4.0501 and a = 80"54' x h i c h a c c o u n t for cer tain l i n e s , w h e r e a s i m p o s i n g a t e t r a o n a l s y m m e t r y r e s u l t s i n a = 4 . 0 2 8 1 . c = 4 . 0 8 4 f w h i c h a c c o u n t f o r t h e res t o f t h e l i n e s . T h e s e v a l u e s a g r e e v e r y w e l l w i t h t h e v a l u e s f o r t h e two p h a s e s as shown i n F ig . 1 i n R e f e r e n c e L11, i n d i c a t i n g t h a t b o t h t h e r h o m b o h e d r a l a n d tetragonal p h a s e s c o e x i s t . I n t h e a b o v e a n a l y s i s , a c o m p u t e r program u s i n g A p p l e m a n ' s l e a s t s q u a r e s method f o r c e l l r e f i n e m e n t 131 was used . C o m p o s i t i o n a n a l y s e s b y e l e c t r o n m i c r o p r o b e were p e r f o r m e d on arrowhead-shaped and r e c t a n g u l a r s a m p l e s f r o m two g r o w t h t r i a l s . T h e c o m p o s i t i o n f o r e a c h s a m p l e was o b t a i n e d from a v e r a g i n g t h e v a l u e s a t f i v e l o c a t i o n s , t h e two ar rowhead-shaped s a m p l e s h a v e 0 .113 a n d 0.117 p a r t s o f T i i n t h e o x i d e f o r m w h i l e t h e two r e c t a n g u l a r o n e s h a v e 0.117 a n d 0.129 p a r t s . The o v e r a l l a v e r a g e o f T i i s f o u n d t o b e .119 p a r t s whereas Zn i s l e a s t h a n t h e p r o p o r t i o n i n t h e s t a r t i n g f o r m u l a PbZn 3Nb 6Ti.103. L o s s o f Z n O t h r o u g h e v a p o r a t i o n took ' p l i c e d u r i n g g r o w t h d u e t o t h e h i g h e r i n i t i a l t e m p e r a t u r e . 3 . D i e l e c t r i c P r o p e r t i e s S a m p l e s i n p l a t e l e t form w i t h t h e major f a c e n o r m a l t o t h e p s e u d o c u b i c [lll] o r I1001 d i r e c t i o n were p r e p a r e d . B a c k r e f l e c t i o n Laue , m e t h o d w a s u s e d i n o r i e n t i n g s a m p l e s . The d i e l e c t r i c c o n s t a n t K a n d l o s s a l o n g t h e p s e u d o c u b i c 11111 a n d [ l o 0 1 d i r e c t i o n s were m e a s u r e d a s a f u n c t i o n o f t e m p e r a t u r e a t f o u r f r e q u e n c i e s : 0 .1 , 1, 1 0 a n d 100 KHz a n d f o r u n p o l e d a n d p o l e d s t a t e s . P o l i n g w a s e f f e c t e d by c o o l i n g t h e s a m p l e f r o m 200°C t o 0°C u n d e r a D C f i e l d o f 1 0 K V l c m . F i g s . 1 a n d 2 show t h e d i e l e c t r i c c o n s t a n t and loss as a f u n c t i o n of t e m p e r a t u r e f o r u n p o l e d s a m p l e s i n t h e [1111 and [ l a 0 1 d i r e c t i o n s , r e s p e c t i v e l y . T h e y s h o w t h e b e h a v i o r o f a r e l a x o r t y p e f e r r o e l e c t r i c . N e a r room t e m p e r a t u r e t h e r e i s a d i f f u s e d t r a n s i t i o n f r o m t h e rhombohedra l to t e t r a g o n a l p h a s e , and a t 1 7 5 ° C a t r a n s i t i o n from t h e t e t r a g o n a l t o c u b i c p h a s e w i t h i n c r e a s i n g t e m p e r a t u r e . F i g s . 3 a n d 4 show t h e e f f e c t o f p o l i n g . P o l i n g a l o n g t h e [1111 a n d L1001 d i r e c t i o n s h a s a v e r y d i f f e r e n t e f f e c t o n t h e K v s T c u r v e s . When p o l e d a l o n g 1 1 1 1 1 , K r i s e s s h a r p l y a t t h e r h o m b o h e d r a l t o t e t r a g o n a l (R-T) p h a s e t r a n s i t i o n , r e a c h i n g a v a l u e o f 1 2 , 0 0 0 s l i g h t l y a b o v e t h e 50000, , 0 . 2 0 CT 0 i L 0.15 5
DOI:
10.1143/jjap.21.1298
发表时间:
1982-01-01
期刊:
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS
影响因子:
--
作者:
KUWATA, J;UCHINO, K;NOMURA, S
通讯作者:
NOMURA, S