A b s t r a c t -A n~o r p h i z a t i o n b y s o l i d s t a t e r e a c t i o n i n Co/Sn n t u l t i l a y e r s h a s b e e n s t u d i e d h y X-ray a b s o r p t i o n s p e c t r o s c o p y i n d i s p e r s i v e mode. The XANES a n d EXAFS p a r t s o f t h e s p e c t r a a r e u s e d t o f o l l o w d y n a m i c a l l y t h e d i f f u s i o n p r o c e s s . I t i s s h o w n t h a t o n a n n e a l i n g , i n -l a y e r c r y s t a l l i n e r e o r g a n i z a t i o n a n d i

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... n t e r d i f f u s i o n o f Co a n d S n o c c u r s i m u l t a n e o u s l y . S i n c e i t s d i s c o v e r y i n 1 9 8 3 / I / , a m o r p h i z a t i o n b y s o l i d s t a t e r e a c t i o n i n n l u l t i l a y e r s h a s a t t r a c t e d much a t t e n t i o n a s a new p r e p a r a t i o n t e c h n i q u e o f nor1 c r y s t a l l i n e s t . a t e s / a / . C o h a l t a n d t i n a m o r p h o u s a l l o y s a r e now w e l l k n o w n , a n d a m o r p h i z a t i o n i n Co/Sn m u l t i l a y e r s was r e p o r t e d t o b e a t w o -s t a g e p r o c e s s / 3 , 4 / . T h e f i r s t s t a q e is t o o f a s t t o b e s t u d i e d b y s t a r r d a r d t e c h n i q u e s , s o we d e c i d e d t o u s e X-ray a b s o r p t i o n s p e c t r o s c o p y i n d i s p e r s i v e mode w h i c h i s p e r f e c t 1 . y s u i t e d t o f o l 1 . 0~ d y n a m i c a 1 p h e n o m e n a i n c o r~d e n s e d m a t t e r p h y s i c s / 5 / . 2. P r e p a r a t i o n a n d e s p e r i m e r~t s T h e s s m p l e s were p r e p a r e d b y a l t e r n a t e e v a p o r a t i o n i n a n u l t r k -h i & vacuum c h a m b e r o f Co 1 9 9 . 1 9 9 X ) .3n6 S n ( 9 9 . 9 9 9 % ) l a y e r : o n t o a K a p i o n p o l y i m i d e s v b s t r a t e a t 776. 1 5 0 b i l a y e r s o f Co ( 1 6 A ) .and S n ( 4 8 A ) were d e p o s i t e d . T h e s a m p l e s were k e p t c o n t i n u , o u s l y i n t o l i q u i d n i t r o g e n u n t i l t h e i r m e a s u r e m e n t s a t L a b o r a t o i r e d ' u t i l i s a t i o n d u H a y o n n e n l e n t E l e c t r o m a g r 1 6 t i q u e ( O r s a y ) . XANES s p e c t r a f lOOeV a b o v e K-edge o f Co, a c q u i s i t i o n t i r e 15s) a n d EXAFS s p e c t r a ( 3 0 0 e V a b o v e K-edge o f Co, a c q u i s i t i o n time 3 s ) w e r e o b t a i n e d a s t e m p e r a t u r e w a s i n c r e a s e d f r o m 77C t o 300G. A t o t a l n u m b e r o f 1 0 0 s p e c t r a h a v e b e e n m a d e , many o f t h e m a r o u n d room t e m p e r a t u r e , w h e r e d i f f u s i o n w a s known t o o c c u r f r o m r e s i s t i v i t y m e a s u r e m e n t s . A Co f o i l w a s a l s o m e a s u r e d f o r c a l i b r a t i o n . Article published online by EDP Sciences and available at http://dx.