ELECTRONIC PROPERTIES OF AMORPHOUS Cu60Zr40 ALLOY

P. Garoche, Y. Calvayrac, J. J. Veyssié
1980 Le Journal de Physique Colloques  
A l t h o u g h amorphous m e t a l s a n d m e t a l l i c glasses h a v e d r a w n much a t t e n t i o n i n t h e l a s t f e w y e a r s , t h e r e a r e s t i l l a number o f u n r e s o l v e d p r o b l e m s c o n c e r n i n g t h e i r e l e c t r o n i c s t r u c t u r e a n d r e l a t e d p h y s ic a l p r o p e r t i e s s u c h as s u p e r c o n d u c t i v i t y , m a g n e t i s m , c o h e s i v e e n e r g y a n d s t a b i l i t y . I n a d d i t i o n t o t h e t h e
more » ... o r e t i c a l d i f f i c u lt i e s i n h e r e n t t o b o t h t h e l o n g -r a n g e a n d s h o r t -r a n g e d i s o r d e r i n t h e s t r u c t u r e o f t h e s e m a t e r i a l s (1) t h e r e i s c l e a r l y t o o a l a c k o f e x p e r i m e n t a l d a t a r e g a r d i n g s ome o f t h e more s i g n i f i c a n t p a r a m e t e r s i nv o l v e d . I n p a r t i c u l a r l o w t e m y e r a t u r e s p e c i f i c h e a t r e s u l t s a r e v e r y s c a r c e . The m a i n r e a s o n i s t h a t v e r y f e w s y s t e m s may be p r e p a r e d i n amorphous b u l k s t a t e a n d t h e s m a l l s a m p l e q u a n t i t i e s g e n e r a l l y av a i l a b l e make a c c u r a t e d a t a d i f f i c u l t t o o b t a i n . T h e r e f o r e we h a v e c o n s i d e r e d o f i n t e r e s t t o u n d e r t a k e a s t u d y o f t h e a -mor~hous a l l o y s s e r i e s Zrx Cul -, . Here we present r e s u l t s f o r x = .4 F i r s t , t h e amorbhous s t a t e i s s t a b l e a t r o o m t e m p e r a t u r e o v e r a r a t h e r w i d e comp o s i t i o n a l r a n g e , g i v i n g t h e o p p o r t u n i t y t o i n v e s t i g a t e t h e t r e n d s o f t h e d e n s i t y o f s t a t e s a t t h e F e r m i l e v e l as a f u n c t ion o f c o m p o s i t i o n . I n t h i s r e s p e c t r e c e n t s t u d i e s b y p h o t o e m i s s i o n s p e c t r o s c o p y h ave r e v e a l e d a d -b a n d s t r u c t u r e w h i c h i s q u i t e c o n t r a s t e d w i t h t h a t o f o t h e r db a n d s y s t e m s ( 2 , 3 ) . w Second, Z r 7 4 Cu2$ h a s b e e n r e p o r t e d t o u n d e r g o a s u p e r c o n d u c t i n g t r a n s i t i o n n e a r 3 K (11) so t h a t a study o f t h e s y s t e m a t i c s o f s u p e r c o n d u c t i v i t y i n t h i s a l l o y s e r i e s i s e x p e c t e d t o p r o v i d e a d e e p e r i n s i g h t i n t o t h e e l e c t r o n i c p a r a m e t e r s i n v o l v e d . T. R i z o g u c h i e t a l l ( 4 ) h a v e r e p o r t e d s p e c i f i c h e a t d a t a on CuS7 Z r 4 3 amorphous a n d c r y s t a l l i s e d a l l o y s b u t a c c o r d i n g t o t h i s a u -t h o r s t h e i r c r y s t a l l i s e d a l l o y s h o u l d b e a m i x t u r e o f Cu3 Z r 2 a n d Cu Z r . As a p a r t o f a c o n t i n u i n g s t u d y o f t h e s t r u c t u r a l , t h e rmal and s u p e r c o n d u c t i n g p r o p e r t i e s o f t h i s a l l o y s e r i e s we p r e s e n t , i n t h i s p a p e r , r es u l t s o f s 2 e c i f i c h e a t m e a s u r e m e n t s on t h e a l l o y Z r 4 0 C U~~ f o r b o t h t h e amorphous a n d c r y s t a l 1 i n e f o r m s . The s t a r t i n g a l l o y has b e e n p r e p a r e d f r o m e l e c t r o t y t i c c o p p e r and K r o l l z i r c on i u m b y l e v i t a t i o n m e l t i n g i n o r d e r t o p r e v e n t a n y c o n t a m i n a t i o n f r o m a c r u c i b l e . T h e i n g o t has b e e n s u b s e q u e n t l y b r o k e n i n t o s m a l l f r a g m e n t s a n d t h e amorphous t h i n f oi l s have been obtained d i r e c t l y from l e v i t a t i o n by t h e t w i n -r o l l quenching technique. W e obtained quenched samples i n form o f a r i b b o n w i t h a t y p i c a l t h i c k n e s s o f 1 0 0 p m a n d an a r e a o f s e v e r a l 2 cm . Fig 1-The diffracted X ray intensity Iexp V . S . the diffraction angle 2 8 , for amorphous Cu 6 0 ZrQo a l l o y . The beam divergence f o r curve 1 was 0,25O and that f o r curve 2 was lo. A l l t h e s a m p l e s u s e d h a v e b e e n i n s p e c t e d for c r y s t a l l i n i t y b y X -r a y d i f f r a c t i o n u s i n g Co K~r a d i a t i o n . A t i m e l a p s e s t e p s c a n n i n g d i f f r a c t o m e t e r was a l s o u s e d t o o b t a i n a m o r e d e t a i l e d X -r a y s c a n w i t h a n Article published online by EDP Sciences and available at http://dx.
doi:10.1051/jphyscol:19808191 fatcat:xbdubalq7nhyddluhd574eiinm