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MÖSSBAUER EFFECT STUDY OF K-EFFECT IN Ni-Fe-Mo ALLOY
J. Frackowiak, H. Morawiec, T. Panek, M. Uhlig
To cite this version:
J. Frackowiak, H. Morawiec, T. Panek, M. Uhlig. MÖSSBAUER EFFECT STUDY OF K- EFFECT IN Ni-Fe-Mo ALLOY. Journal de Physique Colloques, 1980, 41 (C1), pp.C1-373-C1-374.
�10.1051/jphyscol:19801141�. �jpa-00219626�
JOURNAL DE PHYSIQUE Colloque Cl, supplkment au n o 1, Tome 41, janvier 1980, page ~ 1 - 3 7 3
~@SSBAUER EFFECT STUDY OF K-EFFECT I N Ni-Fe-Mo ALLOY
J.E. Frackowiak, H. Morawiec, T.J. Panek and M.R. U h l i q
I n s t i t u t e of Physics and Chemistry of Metals, S i l e s i a n University, Poland.
1. Introduction,
-
In general the resist- ivity04
cold worked or quenched samples of an alloy decreases after annealing.Nevertheless in a number of different al- loys the resistivity was found to- incre- ase. This phenomenon is commonly known as the Leffect
[I].
Previously, the K-effect has been ob- served in cold worked Ni-Fedo alloys
(molybdenum permalloys) after heat treat- ment in the temperature range of 673 K to 773 K, Previous investigations suggest
The Massbauer spectra were analysed by J.Hesse and A.Rubartsch method [3] to yield the hyperf ine distributions curves P (H)
.
The spectra of cold-rolled samples were a,
lso indepedently analysed by least-squares fit of Zeeman sextets. The intensity of Zeeman sextets were calculated with as- sumption of random distribution of atoms in the alloy and the position of lines were calculated by assuming validity of the following relations for hyperfine mag- netic fields and isomer shift:
that the formation of Lstate in Ni-Fedbo
~(n,m)l H~+$[%~ (i)A%i (i)+%, (i)nrto (i)] alloy is connected either with segregation
ls(n,m)=lso+flnNi (i). ISIT$i) (1). IS&)] of Yo atoms or with formation of different
forms of short range order. Recently Taunt and Ralph [2] investigated Letate in Ni-Fe- Mo alloy by fieletion microscopy. They ob-
served existence of ordered Ni3Fe domains and small precipitates composed of Ni, Fe and lo atoms.
In this paper the K-state in Ni-.Fe-Xo alloy has been investigated by Mossbauer effect to yield informations about local distribution of atoms in the alloy.
2. Material and experimental technique.
-
In this work the Ni-17.2 at.% Fe-3 at.% Mo alloy was investigated. The samples were initialy cold-rolled. In the first series of measurement the initial eamples were annealed at 673 K for 6 and 40 hours and slowly cooled to room temperature. In the second series the initial samples were an- nealed at 1173 K for 3 hours and slowly cooled and then annealed at 673 K for 6 hours. The annealing temperature 673 K was chosen as the best temperature for format- ion of K-state in the alloy.
Resistance measurements have shown that for all samples annealed at 673 K resist- ivity increases about 10% in comparison to cold-rolled samples.
where:AHX(i) are contributions of the mag- netic field at the central Fe atom due to one n.n. or n,n.n. solute atoms X=Ni, No and ISX(i) are similary defined changes of the isomer shift, nNi (i) and %o (i) are the number of neighbors in i-th coordi- nation sphere of Fe atom, Ho and ISo are constant values of magnetic field and iso- mer shift.
Using the fitting procedure we obtained values:
A+(I)= -10.0 kOe, hflNi(2)= -3.8 kOe, A%,(?)= -32.2 kOe, AfENo(2)= -32,O kOe, ISNi (I )= O.OOImm/sec, ISNi (2)- O.OOmm/sec,
Isdo
(I )=-O.Olm/sec, I%o (2)=-0,Olmm/sec.These values are in good egreement with suitable ones for Ni3Fe alloy [4] and FeAIo dilute alloy [5].
3.
Results and discusion.-
The hyperfine field distribution P(H) for a cold-rolled sample calculated by two method described in section 2 are compared in Fig. 1.It is seen that these distributions are very similar. Real differences appear for region of effective fields (272-280) kOe and for fields less then 230 kOe. The sec- ond region is connected with Fe atoms sur-
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19801141
c1-374 JOURNAL DE PHYSIQUE
Fig. 1.
-
Hyperfine f i e l d d i s t r i b u t i o n f o r col&olled Ni-Fe-Edo a l l o y c a l c u l a t e d a ) by J.Hesse and A.Rubartsch method;b) with assumption of random d i s t r i b u t i o n of atoms i n t h e a l l o y .
rounded by one o r two Yo atoms. The great- e r p r o b a b i l i t y t o f i n d Fe atoms with one and two Mo atoms a s neighbours i n compari-
Fig. 2.
-
Byperfine f i e l d d i s t r i b u t i o n f o r Ni-FeAo a l l o ya ) c o l d - r o l l e d sample;
b) a m p l e annealed a t 673 K f o r 6 hours.
which p r o b a b i l i t y i n c r e a s e i n L s t a t e . The i n c r e a s e i n p r o b a b i l i t i e s of exist- son t o random d i s t r i b u t i o n of atoms sug- ence of magnetic f i e l d s i n region (240
-
g e s t s t h a t d i s t r i b u t i o n of Mo atoms i n 264) kOe can be connected with two d i f f e r - c o l d s o l l e d samples i s not uniform. e n t groups of configurations.
After annealing a t 673 K t h i s d i s t r i b - In the first group t h e Fe atoms have t i o n becomes more uniform. For example i n (11-12)Ni atoms i n t h e f i r s t coordination Fig.2 t h e hyperfine f i e l d d i s t r i b u t i o n s sphere and (5-6)Ni atoms i n t h e second P (H) a r e compared f o r c o l d - r o l l e d and an, sphere. It means t h a t in L s t a t e t h e s h o r t nealed a t 673 K sample. Decrease i n proba- range order l i m i t e d t o t h e f i r s t c o o r d t b i l i t i e s of existence magnetic f i e l d s l e s s n a t i o n sphere a r i s e s .
than 230 kOe i s seen. It p o i n t s out t h a t The second group of configuration i s number of No atoms near Fe atoms i s re- c h a r a c t e r i s e d by (%lO)Mi atoms i n the duced. Similar r e s u l t w a s obtained in[6] f i r s t coordination sphere, (4-5)EIi atoms where s e v e r a l Ni-Feao a l l o y s were inves- i n t h e second sphere and 1 Mo atom i n t h e t i g a t e d by Mbasbauer spectroscopy. f i r s t o r second coordination sphere. It
It i s a l s o seen t h a t d i s t r i b u t i o n maxi- suggests t h a t only s p e c i f i c configurations mum i s s h i f t e d i n d i r e c t i o n of lower f i e l d of Fe atoms w i t h one Mo atom a s n.n. o r and the maximum value i s g r e a t e r than t h e n.n.n. a r e found i n L s t a t e .
one f o r c o l d - r o l l e d sample. Basing oneself on t h e assumption t h a t values o f ~ % ( i ) and I S X ( i ) remain constant during annealing a t 673 K we can describe t h e c o n f i g u r a t i o n s
References
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Z.Petallkunde, ~ ( 1 9 5 0 ) 185 [4] DR1JVER.J.W. and VAN DER WOUDE,P., TAU~~P,R.I. and RALPH,B., RADELAAR,S., Phys, Rev. B, l6(1977)985N a t . Sci., (1 751185 [~]vII?czE,I. and CAMPBELL,I.A.,
mss~.J. an%
&humTSCH,A., J. Phye. F, 2(1973)647J. ~ h y s . E,1(1974)526 [6] MAXAROV, W. A , , PUZEY, I.M. and SAKHAROVA, T., Mz. Met. i Metall., 2(1973)720
