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HAL Id: jpa-00219649

https://hal.archives-ouvertes.fr/jpa-00219649

Submitted on 1 Jan 1980

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MÖSSBAUER STUDY OF PROTON RADIATION EFFECTS IN PERMALLOY

M. Kopcewicz, A. Kotlicki, M. Lipska

To cite this version:

M. Kopcewicz, A. Kotlicki, M. Lipska. MÖSSBAUER STUDY OF PROTON RADIATION EF- FECTS IN PERMALLOY. Journal de Physique Colloques, 1980, 41 (C1), pp.C1-419-C1-420.

�10.1051/jphyscol:19801162�. �jpa-00219649�

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JOURNAL DE PHYSIQUE Colloque C1, supplkment au no 1 , Tome41, janvier 1980, page C1-419

M~~SSBAUER SNDY OF PROTON RADIATION EFFECTS IN P E R M A W

M. Kopcewicz, A. Kotlicki and M. Lipska

I n s t i t u t e of ExperirnentaZ Physics, Warsaw University, Hoia 6 9 , 00-681 WarsW, Poland.

I n the recent years we studied prot- on radiation e f f e c t s i n various d i e l e c t r i c iron compounds by the Mllssbauer technique.

We observed such radiation e f f e c t s as ra- diation damage due t o proton irradiation, chemcal changes i n the irradiated material location of iron ions in the i n t e r s t i t i a l positions in the l a t t i c e , oxydation of Fez+ t o ~ e ~ + , Formation of the superpara- magnetic phase of the magnetic material due t o radiative decomposition was obser- ved and veryfied by Mbssbauer measurements

Sn a wide temperature range [1-4].

I n the present paper some r e s u l t s of a Mbssbauer studyof the e f f e c t of 1.8 MeV proton irradiation on permalloy a r e repor- ted, Suplementary X-ray studies of the ir- radiated samples were performed t o deter- mine the material formed during irmdia- tion.

Permalloy f o i l s of the composition

integrator, After imgdiation each sample was measured a s stationary absorber in a

constant acceleration Nokia Electronics 80, Pl8ssbauer spectrometer using a 5 7 ~ o i n palladium source of 10 mCi activity. The M6ssbauer measurements were carried out se- veral days a f t e r irradiation so only the stable changes due t o Irradiation were ob- servad. The measurements were performed in the temperature range 78-30013: using the Oxford Instruments Co. continuous flow cryostat

.

The parameters of the M6ssbauer spec- tra such as the l i n e positions, i n t e n s i t i e s linewidths and the nonresonant background l e v e l were calculated by the l e a s t square method, the Lorenzian shapes being f i t t e d t o the experimental data obtained,

The Mbssbauer spectrum of n o n i m d i a - ted permallay f o i l consists of six linea of magnetic hyparfine sp'littlng /hfs/ (Fig.1~) 7496Ni-2-e and 50%t?i-509@e, rolled t o a

thiclnress of 30

pm

and annealed i n vacuum f o r several hours a t 1200K were irradiated I n the Warsaw Van de Oraaff accelerator.

Protons of energy 1.8 MeV and doses of 40" t o 5 x 1 0 ~ ~ were used. Tbe i r r a d i a t i v e

arrangement consisted of the proton beam VELOCITY collimator and water owled sample holder. Fig.1

The irradiated area was about 10 nun2* The Irradiation w i t h protons of energy 1.3 MeV proton dose was measured with a current and dose up to 5x10'~ does not a f f e c t sig-

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19801162

(3)

c1-420 JOURNAL DE

nif icantly the spectrum shape ( ~ i g. IB,IC).

However, the r a t i o s of the intensity of the first t o second and sixth to f i f t h l i n e of the hfs spectrum increasein the case of Per-

mellw

749@i-24%Fe from 0.80 t o 1 -05 f o r fncreasing proton beam current. The obser- ved increase of this r a t i o (Fig,2) suggests that irradiation makes the magnetic f i e l d

direction distribution in the irradiated sample more random than it is in a nonir- radiated one. A similar but less d i s t i n c t

1 7 -

behaviour was ob-

served f o r pennal- lay 5096Ni-5-e. In spectra of the f o i l s irradiated with doses of more .than 9x10~9 protons,

I I -

0 :

C

(L In-

> .

t .

In

W .

C

I"-

"

z 2

d

I

,

;

,_I

an additional quad- F i g 2 rupole s p l i t t i n g

- -

doublet /QS/ appears beside the s i x lines of the magnetic hfs w i t h an isomer s h i f t of 0.94 mm/s with respect t o metallic iron and quadrupole s p l i t t i n g of 0.66 ~mn/s

f F i g . l ~ ) . Mf5ssbauer measurements performed

i n the temperature range 78-300K (~ig.3)

.m

.

show t h a t the QS

m"

doublet disappears

P a ,

a t about 207K. This suggests that the QS doublet corres- ponds t o the forma- tion of a material

VELOCITY ""l revealing a magne-

Fig03 t i c transition a t about 207K and the hfs lines corresponding t o this meterial are not resolved frola the permalloy lines.

PHYSIQUE

I n the X-ray spectrum of the sample f o r which the QS doublet was observed the distinct; l i n e s corresponding t o the FeO oxide were found. The parameters of the doublet are irr good agreement w i t h those observed f o r FeO [5,63.

The s t a b i l i t y of the material formed whose content in the sample did not change even a f t e r several months f r o m irradiation, suggests that it was formed in the bulk of the irradiated penualloy and not on its surface.

The oxygen necessery f o r FeO f orma- tion was probably contained in the sample i n the intercrystalline spaces.

The authors are indepted t o D r I.

Sosnarska f o r her kind interest i n this study. Thanks are also due t o Dr T-Panek of the Silesian University for making available the Fe-Ni samples, and t o Mr.

S .Fi jakkowski f o r technical assistance.

1. M.Kopoewicz, A.Kotlicki, Rad.Eff.

24,

(1975) ,267.

2. M.Kopcewicz, A.Kotlicki, M.Szefer,

~ h y s . ~ t a t . ~ o l . / a / a , (1975) ,635.

3. A.Kotlicki, N.Boye Olsen, J.Staun Olsen, Rad.Ef f

. 28,

(1 976) ,1.

4. M.Kopcewicz, A.Kotlicki, Solid State Commun.

3,

(1 978) ,1409.

5. G

.

Shirane

,

DOE .Cox, S .L.Ruby, Phy s .Rev.

B,

(1962) ,1158.

6. D.P.Johaon, Solid S t a t e Commun.

2,

(7 969) ,I 785.

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