HAL Id: jpa-00219784
https://hal.archives-ouvertes.fr/jpa-00219784
Submitted on 1 Jan 1980
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
A SYSTEMATICAL ANALYSIS OF METALLIC GLASS MÖSSBAUER SPECTRA
L. Takács
To cite this version:
L. Takács. A SYSTEMATICAL ANALYSIS OF METALLIC GLASS MÖSSBAUER SPECTRA.
Journal de Physique Colloques, 1980, 41 (C1), pp.C1-265-C1-266. �10.1051/jphyscol:1980191�. �jpa-
00219784�
JOURNAL Dl3 PHYSIQUE
Colloque C1, suppldment au n
O1 , Tome 41, janvier 1980, page C1-265
A SYSTEMATICAL ANALYSIS OF METALLIC GLASS M~SSBAUER SPECTRA
L. Tak6cs
Central Research Institute for Physics, H-1525 Budapest, P.O.B. 49, Hungary.
M o s s b a u e r s p e c t r o s c o p y on f e r r o m a g n e - t i c m e t a l l i c g l a s s e s c a n b e u s e d t o s t u d y t h e i r m a g n e t i c p r o p e r t i e s , e l e c t r o n i c s t r u c - t u r e a n d e v e n t h e s h o r t r a n g e s t r u c t u r a l o r d e r . The s p e c t r a c o n s i s t o f s i x b r o a d , h i g h i l y o v e r l a p p i n g l i n e s . The m a i n c a u s e o f t h e l i n e b r o a d e n i n g i s t h e d i s t r i b u t i o n o f t h e h y p e r f i n e f i e l d s .
The d e t e r m i n a t i o n o f t h e h y p e r f i n e f i e l d d i s t r i b u t i o n c a n b e c a r r i e d o u t b y ( i ) a s s u m i n g a g i v e n s h a p e f o r p ( H ) [l] o r ( i i ) b y u s i n g a s e r i e s e x p a n s i o n 123 o r a n i n t e g r a l e q u a t i o n [3] m e t h o d . I n t h e f i r s t c a s e t h e p a r a m e t e r s o f P ( H ) c a n b e d e t e r - m i n e d b y a l e a s t - s q u a r e s p r o c e d u r e b u t t h e a s s u m p t i o n o f a n u n j u s t i f i e d s h a p e c a n l e a d t o m i s l e a d i n g c o n c l u s i o n s . I n t h e s e c o n d c a s e p ( ~ ) h a s p h y s i c a l l y u n r e a l i s t i c o s - c i l l a t i o n s .
T h e aim o f t h e p r e s e n t i n v e s t i g a t i o n w a s t o s t u d y t h e s i g n i f i c a n c e o f t h e m o s t i m p o r t a n t p h y s i c a l p a r a m e t e r s . B i n o m i a l d i s t r i b u t i o n o f h y p e r f i n e f i e l d s
h a s b e e n a s s u m e d , b e c a u s e t h e s h a p e of t h i s d i s t r i b u t i o n c a n b e c h a n g e d b y v a r y i n g x
14).
x = 0 . 5 c o r r e s p o n d s t o a s y m m e t r i c a l s h a p e , a t x = 0 . 2 a n d 0 . 8 p ( ~ ) h a s a n 8%
l o n g e r t a i l o n t h e l o w a n d h i g h f i e l d s i d e , r e s p e c t i v e l y . ( T h i s f o r m u l a w a s u s e d w i t h -
o u t r e f e r i n g t o a n y s t r u c t u r a l m o d e l w i t h c o o r d i n a t i o n n u m b e r N a n d c o n c e n t r a t i o n x . ) N h a s b e e n c h o s e n t o 2 0 t o g e t a r e l a t i v e l y s m o o t h d i s t r i b u t i o n . A s t h e s p e c t r a w e r e a s y m m e t r i c a l , c o r r e l a t e d c h a n g e s o f t h e h y p e r f i n e f i e l d a n d i s o m e r s h i f t h a v e b e e n a s s u m e d b y s u p p o s i n g t h e i s o m e r s h i f t o f t h e s u b s p e c t r a t o b e i = i + n A i .
To h a v e a n i n t e r n a l c o n t r o l of t h e d a t a e v a l u a t i o n t w o s p e c t r a w i t h d i f f e r e n t i n - t e n s i t y r a t i o s h a v e b e e n m e a s u r e d . T h e s a m p l e s w e r e p o l a r i z e d b y a s m a l l permanent m a g n e t i n t h e s a m p l e p l a n e a n d t w o s p e c t r a w e r e t a k e n w i t h d i f f e r e n t a n g l e s b e t w e e n t h e s a m p l e p l a n e a n d t h e y - r a y d i r e c t i o n [4]. The r e l a t i v e i n t e n s i t y o f t h e p e a k s w e r e a b o u t ( a ) 3 : 3 . 8 : 1 . 1 a n d ( b ) 3:1.2:1.1.
1 0 2 4 - c h a n n e l s p e c t r a w e r e m e a s u r e d w i t h a b a s e - l i n e o f a b o u t 3 0 0 . 0 0 0 a n d maximum peak h e i g h t o f 1 5 . 0 0 0 c o u n t s p e r c h a n n e l , r e s - p e c t i v e l y .
I n F i g u r e s 1 a n d 2 t h e r e s u l t s o f a s e r i e s o f d a t a e v a l u a t i o n s on t h e r o o m t e m - p e r a t u r e s p e c t r a o f t w o F e B m e t a l l i c
I - c c
g l a s s e s a r e shown a s a f u n c t i o n o f x . The l o w v a l u e s o f
X
i n d i c a t e t h e v e r y goodr e d
d e s c r i p t i o n o f t h e s p e c t r a . The q u a l i t y o f t h e f i t s d o e s n o t d e p e n d s t r o n g l y o n t h e s h a p e o f t h e d i s t r i b u t i o n - t h e s t a t i s t i c a l u n c e r t a i n i t y o f X i s 0 . 0 5 . The m i n i m a
r e d
f o r t h e s p e c t r a w i t h d i f f e r e n t i n t e n s i t y
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1980191
c1-266
JOURNAL DE PHYSIQUEFig. 1 . : The reduced
x2,
t h e width of p(H), a ,'ii
Fig. 2 . : The same a s Fig. 1 f o r an Fe75*6B24.4 and 1, f o r a n Fe B m e t a l l i c g l a s s . The in- m e t a l l i c g l a s s .t e n s i t y r a t i o s $)'3:4.8:1.1 ( 0 ) and 3:1.2:1.1
( x )
s h i f t i s i n s e n s i t i v e t o a s well a s t o t h e r a t i o s a r e a t d i f f e r e n t x v a l u e s , t h u s t h e
s h a p e o f p ( H ) i s r a t h e r i l l - d e f i n e d . On t h e o t h e r h a n d , t h e w i d t h o f t h e h y p e r f i n e f i e l d d i s t r i b u t i o n i s w e l l d e f i n e d a n d e q u a l s t o 3 1 . 5 ~ 1 kOe.
The a v e r a g e h y p e r f i n e f i e l d s d e t e r - m i n e d f r o m s p e c t r a w i t h i n t e n s i t y r a t i o ( a ) a r e s y s t e m a t i c a l l y l o w e r b y 1-3 kOe t h a n t h o s e f r o m s p e c t r a (b). The r e a s o n o f t h i s d e v i a t i o n i s n o t q u i t e c l e a r , y e t , b u t
-
t b g e t h e r w i t h t h e x d e p e n d e n c e
-
it d o e srt-
n o t make p o s s i b l e t h e d e t e r m i n a t i o n o f t h e a d e r a g e h y p e r f i n e f i e l d w i t h a n a c c u r a c y b e t t e r t h a n ?2-3 kOe. The a v e r a g e i s o m e r
i n t e n s i t y r a t i o . F o r t h e s p e c t r a w i t h i n - t e n s i t y r a t i o s ( a ) a n d ( b ) t h e v a l u e o f A ~ / A H i s 8 x 1 0 ~ ~ a n d 3 - 5 x 1 0 - ~ m m / s e c / k o e , r e s p e c t i v e l y . The a g r e e m e n t c o u l d n o i b e i m p r o v e d by a l l o w i n g f o r q u a d r u p o l e i n t e r - a c t i o n s t h u s A i c a n n o t b e a c c e p t e d a s a p h y s i c a l q u a n t i t i y .
1 . Sharon,T.E. and Tsuei,C.C., SSC
9
(1971) 1923 2. Window,B., J.Phys.E:Sci.Inst.4
(1971) 401 3. Hesse,J. and Riibartsch,A., J . P ~ ~ s . E : S c i . I n s t .1
(1974) 5264. Vincze,I. 'and ~ak'acs,L.', h.oc.Int.Conf. on G s s - bauer Spectroscopy, Bucharest, 1977, p.419 and Vincze ,I., S o l i d S t a t e Commun.