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Submitted on 1 Jan 1980
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PECULIARITIES OF THE SPIN STATE AND THE DISTRIBUTION OF Fe3+ IN SODIUM BORATE
GLASSES
V. Imshennik, I. Suzdalev, Yu. Maksimov, F. Litterst
To cite this version:
V. Imshennik, I. Suzdalev, Yu. Maksimov, F. Litterst. PECULIARITIES OF THE SPIN STATE AND THE DISTRIBUTION OF Fe3+ IN SODIUM BORATE GLASSES. Journal de Physique Colloques, 1980, 41 (C1), pp.C1-267-C1-268. �10.1051/jphyscol:1980192�. �jpa-00219785�
JOURNAL DE PHYSIQUE Colloque Cl , supplPment au n O 1 , Tome 41, janvier 1980, page C1-267
PECULIARITIES OF THE SPIN STATE AM) THE DISTRIBUTION OF ~ e IN ~ SOD1 + UEl BORATE GLASSES V.K. Imshennik, I.P. Suzdalev, Yu.V. Maksimov and F.J. Litterst +
I n s t i t u t e of ChemicaZ Physics, Moscow, USSR.
+
Physic Department E-15 der Technischen Universitift, Munchen, BRD.:....
a... ....
Mossbauer spectroscopy, ESR, and X = i Q % ,..-....,,.,,,*
...
... .:.
magnetic s u s c e p t i b i l i t y rneasurments were
- .
.C%=5% .. 6
used t o i n v e s t i g a t e the s p i n s t a t e and ..&..-a- .,..
. . .: , . -
,.
.
the d i s t r i b u t i o n of ~ e i n sodium borate ~ +
. . . . ....
....
g l a s s e s (Na20. 3B203: xJ?e203 where x=O.I,
I.5,IO a t %).
.
Mossbauer s p e c t r a a t 4.2 K-= T c300 K
c o n s i s t of the doublet with A Eg =I .I+O.I
. . .
mm/s IS=0.40+0.03 mm/s ( r e l a t .A -Fe )and
t h e magnetic hyperfine structure(HFs)
... . .
:....with HA! =52.0&0.5l!, 1 ~ = 0 . ~ 6 ~ 0 . 0 3 mm/p(re-
l e t , o~ -Fe). A t small concentration of
. . . ..:.
X.i r o n (x=o.I,I%~ t h e We, i s predominact i n epectra (fig.11, the ESR s i g n a l s with
8 -=
4.3 i s observed a n d the magnetil;s-- Pig.1.- Mossbauer s p e c t r a of g l a s s e s a t t i o n d a t a ( f i g . 3 ) correspond t o S=5/2 T = 80 K.parkmagnetic s t a t e . When the c o n c e n t ~ a - -':
.
t i o n of i r o n i n c r e a s e s the doublet becom- e s more i n t e n s i v e than the hf s t r u c t u r e and strong s i g n a l ESR with
$
T 2 occursa t 4.2 K C T 7 300 K but the e a t u r a t i o n magnetization decreases ( f i g . 3 ) . It i s
obvious t h a t the hf s p e c t r a appear due t o slow r e l a x a t i o n r a t e of i s o l a t e d pe3+
i o n s homogeneously d i s t r i b u t e d i n g l a s s y matrix.
Application of a s m a l l e x t e r n a l mag- n e t i c f i e l d breaks the bond between the e l e c t r o n i c and n u c l e a r s p i n s and the hf s p e c t r a become more resolved.
The hf s p e c t r a of f i g 2 obtained under ffext=0.065 T were f i t t e d with the model of 3 s e x t u p l e t s ( S ~ Y 5/2,f3/2.&lh
E l a c c o r d i n g t o t h e H a m i l t o n i p ( I ) . H = D ( % ~ - I / ~ S(S+I)
+>(s:
-Sy)) ( I ) by using the program given f nt 21.
T h i s. -
computer f i t g i v e s
A
-0.22i0.02 f o r P I -2.-CompLter f i t a p e c t ~ a of ~ 0 . 1 % ~% f; %,under Hext-0.065 T a t T = 4.2 K,
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1980192
c1-268 JOURNAL DE PHYSIQUE
Fig. 3. The magnetiaation p e r ~ e 3 ' i o n f o r d i f f e r e n t x a s a f u n c t i o n of a p p l i e d magnetic f i e l d a t T 4 . 2 K.
- - -
Thesimple B r i l l o u i n function.--- The B r i l l o -
*&n f u n c t i o n c o r r e c t e d f o r a n i s o t r o p i c values.
x=I%, A=0.24&0.03 f o r x = O . I % and A E q '0.1% 0.04 mm/s f o r both samples.
The f a c t of d e s c r i p t i o n t h e hf s p e c t r a w i t h one value of
A
which i s about equal f o r -1% and&o.I$
i n d i c a t - e s t h e s i m i l a r i t y of d i s t o r t e d octahedral environment of ~ e ~ + i o n s , and theref o r e t h e s i m i l a r i t y of s t r u c t u r i a l u n i t s i n g l a s - sy matrix where pe3+ions p l a c e a s modi- f i e r .It should be n o t i c e d t k a t t h e cor- r e c t value of quadrupole s p l i t t i n g of t h e hf s p e c t r a mentioned above can be obtai*
ed only from S,=+5/2 Kramers doublet.
This doublet y i e l d a n i s o t r o p i c
3
v a l u e s a t anyA la
and t h e r e f o r e e l e c t r o n i c and n u c l e a r s p i n s a r e d i r e c t e d along z a x i s"of 'the H a m i l t o n i a n ( I ) , w h i c ~ i s c o l l i n e a r o r k a s the c o n s t a n t a n g l e with t h e main axes of t h e ef g r a d i e n t . I t i s necessary t o n o t e t h a t the computer f i t t e d magnetid z a t i o n c u r v e s ( f i g . ? ) were c o r r e c t e d f o r a n i s o t r o p i c
9
v a l u e s too.The d i f f e r e n c e of quadrupole s p l i t t i n g of doublet and hf s t r u c t u r e snows, t h a t t h e doublet d o e s n ' t a r i s e from f a s t r e l a x a t i o n p r o-
c e s s and most probably has another natu- r e .
Decreasing of magnetization w i t h the i n c r e a s e d c o n c e n t r a t i o n of i r o n prove t h e e x i s t e n c e of an a n t i f erromagnetic i n t e - r a c t i o n between ~ e ~ + i o n s . ~ u t a n t i f e r r o - m a g n e t i c a l l y coupled dimers and superpa- ramagnetic c l u s t e r s of Be3'ions don1 t produce low temperature ESR s i g n a l due
t o s i n g l e t . ground l e v e l .Only t r i m e r s y i e l d such s i g n a l .According t o magnetiza-
t i o n d a t a we suggest t h e e x i s t e n c e of both t h e a n t i f e r r o m a g n e t i c a l l y coupled dimers and t r i m e r s of rle3+ i o n s .
The r e l a t i v e amount 9f i s o l a t e d i o n s
! Zl ) w i t h t h e magnetic moment/=
vb
t h er e l a t i v e amount of i r o n atoms i n dimers (z2)with/r2=0 and t r i m e r s ( Z j ) w i t h / u 3 = I p a [3J we can g e t from f o l l o w equation9,as- suming Z1+Z2+Z3=I. Sd/St = Z 2
+
Z3.M
=PI
E(r1X/kT) .Zq+/u3
B(r3H/kT). Z 3 where B - E r i l l o u i n f u n c t i o n , sdand St aret h e a r e a s of doublet and t o t a l one i n mossbauer s p e c t r a f o r t h i n absorber a t T=4.2 K.The r e s u l t s of numerical ca1Cul.a- t i o n s a r e given i n t h e Table.
Cencentr.% 0.1 I 5 1 0
2
1-
0.9 0.1 -0.25 w0.25 -0.2-
z2 - - -
0.5-
0.81 2
should be mentioned t h a t due t o a Bolt zmann p o p u l a t i o n of high l e v e l s I p " ~ / ? J 2/@nd theref o r e t h e v a l u e s of L b l e a r e obtained w i t h e r r o r 05: 10-20%.Thus we can make t h e conclusion t h a t i n t h e c a s e of $odium b o r a t e g l a s s e s there a r e non-equivalent s p o s i t i o n s of F'e3*iona i n g l a s s y matrix.These p o s i t i o n s can be connected w i t h the f i v e c r y s t a l l i n e s t r u c - t u r i a l groups f ounc! i n i43and c o n t a i n i n g B03and B04 u n i t s w i t h b r i d g i n g and non- b r i d g i n g oxygen atoms. The e x i s t e n c e of both types of oxygen atoms as n e a r e s t heighbours d i s t o r t t h e l o c a l i w i r o u n m e n t
of ~ e ~ + a n d produce
, !
~0.23 f o r i s o l a t e d i o n s and supply a n t i f erromagnetic emhan- g e f o r dimers and t r i m e r s . The p e c u l i a r i - t i e s of d i s t r i b u t i o n a r e t h a t , t h e s i t e s aP i s o l a t e d i o n s a r e occupied f i r s t of all and than t h o s e of dimers and t r i m e r s .References
.
I.Wickman H.H.,Klein,lf.P.Shirley D.Ai Phys .Rev, 152(1966)345.
2.Im~hennik~V.K. ,Afanasqev,A.I. , l a k a r o v E.P,,Goldanskii,V.I.,Plachinda A . S . , Suzdalev I.P. ,Fiz.Tverd.fel.I5(1973)2656.
3.Earnchaw A. , F i g g i s B.B.,Lewis J.
H.Chem.Soc. A 12(1966)1657.
4.Yellison G.E.Ir., B r a y P.J. J.Non- C r y s t a l l i n e S o l i d s 29(1978) 187.
