PROCEEDINGS
NUKLEONIKA 2003;48(Supplemen 1):S85−S88
In oduc ion
A numbe o speci ic p ope ies − bo h magne ic and
mechanical − o nanoc ys alline alloys based on Fe a e
a consequence o hei complex s uc u e. Among hem,
so called FINEMET- ype and NANOPERM sys ems
dis inguish hemsel es by so magne ic beha io [3, 6,
7]. Ma e ials cons i u ed o i on-me alloid based alloys
(70−80 a .% o Fe) wi h addi ion o Cu and Nb − in o de
o modi y g ain g ow h − belong o he o me g oup.
Nanoc ys alline FINEMET- ype alloys a e p oduced by
con olled annealing o amo phous ibbons, which esul s
in p ecipi a ion o c ys alline g ains om diso de ed ma ix.
Magne ic p ope ies o hus ob ained ma e ials s ongly
depend on he amoun o c ys alline phase, shape and size
o g ains, s uc u e and chemical con en o bo h c ys alline
and amo phous egions, in e ac ions be ween g ains and
a coupling be ween g ains and he ma ix. Beside o he
pu e c ys alline phase inside g ains and he amo phous one,
bounda ies egions a e impo an ha comp ise a oms
si ua ed on he su ace o g ains and in i s icini y. Al hough
numbe o au ho s poin o he ole o hese egions o
magne ic p ope ies o nanoc ys alline alloys, i is no easy
o e idence he su ace e ec s expe imen ally, pa icula ly
in he case o FINEMET, because o complica ed s uc u e
o g ains in hese ma e ials. High ini ial magne ic pe -
meabili y and low coe ci i y a e cha ac e is ic o nanoc ys al-
line FINEMET ibbons. Excellen so magne ic p ope ies
o hese alloys a e ele an o he e y small alue o mag-
ne os ic ion, which plays an impo an ole on p ope ies
o sys ems wi h a ious coexis ing phases
dis ibu ed in
egions o nanome e s sizes, because o s esses
in ol ed by
di e en a omic a angemen and, consequen ly,
di e en
densi y, he mal expansion and o he eal physical
peculia i ies.
Hype ine ields
and magne oelas ic su ace e ec s
in Fe72Cu1.5Nb4Si13.5B9 nanoc ys alline alloy
Tadeusz Szumia a,
Michał Gaw oński,
Bogumił Gó ka,
Ka a zyna B zózka,
Ja ie S. Blázquez-Gámez,
Tadeusz Kulik,
Rysza d Żube ek,
Anna Ślawska-Waniewska
T. Szumia a, M. Gaw oński, B. Gó ka, K. B zózka
Depa men o Physics,
Technical Uni e si y o Radom,
29 Malczewskiego S ., 26-600 Radom, Poland,
Tel.: +48 48/ 361 78 46, Fax: +48 48/ 361 78 03,
e-mail: [email p o ec ed], [email p o ec ed]
J. S. Blázquez-Gámez
Depa amen o de Física de la Ma e ia Condensada,
Uni e sidad de Se illa,
Ap. 1065, 41080 Se illa, Spain
T. Kulik
Facul y o Ma e ials Science and Enginee ing,
Wa saw Uni e si y o Technology,
141 Wołoska S ., 02-507 Wa saw, Poland
R. Żube ek, A. Ślawska-Waniewska
Ins i u e o Physics, Polish Academy o Sciences,
32 Lo ników A e., 02-668 Wa saw, Poland
Recei ed: 17 July 2002, Accep ed: 20 Janua y 2003
Abs ac In his wo k hype ine ields o wo-phase nanoc ys alline Fe72Cu1.5Nb4Si13.5B9 alloys we e s udied in o de o e i y
he exis ence o su ace e ec s. To ob ain a se ies o nanoc ys alline samples wi h small g ains o di e en sizes, a special non-
-iso he mal annealing p ocedu e o an ini ially amo phous ibbon was applied. In he case o samples wi h a signi ican amoun
o c ys alli es, a high ield (abou 27.5 T) componen o con inuous pa o he hype ine ield dis ibu ion was ound ha could
be a ibu ed o bounda y egions be ween he g ains and es o he sample. The exis ence o he su ace e ec s was con i med
in he magne os ic i e expe imen .
Key wo ds FINEMET • Mössbaue spec oscopy • nanoc ys alline alloys • su ace e ec s • su ace magne os ic ion
T. Szumia a e al.
S86
Expe imen al de ails and cha ac e iza ion o samples
FINEMET- ype amily de i es om he alloy wi h
he nominal composi ion o Fe73.5Cu1Nb3Si13B9 [5, 15]. In
o de o p epa e a se ies o nanoc ys alline samples wi h
small g ain sizes and a la ge amoun o su ace egions, an
ini ially amo phous ibbon o modi ied con en o
Fe72Cu1.5Nb4Si13.5B9 (wi h small excess o niobium and
coppe in ela ion o classical FINEMET), ob ained by he
apid quenching me hod, was subjec ed o a non-iso he mal
annealing p ocess. In he i s s age o annealing, he
empe a u e was aised in abou 3 min o he maximal alue
600–725°C o a ious samples, and in he second one he
empe a u e was educed wi h a simila a e. A small
u nace connec ed wi h a DSC se (di e en ial scanning
calo ime y) made i possible ap ecise con ol o empe a-
u e a ia ions. This complica ed p ocedu e enabled
e ec i e p oduc ion o small c ys alli es o di e en sizes,
depending on he maximum empe a u e applied.
Samples ha e been cha ac e ized by X- ay di ac-
ome y and elec on mic oscopy. Sizes o c ys alline g ains
ha e been e alua ed om he wid h o e lec ions.
Independen ly, hese alues we e de i ed om elec on
mic og aphs. A e age diame e alues all in he ange
5 nm < D < 12 nm; he la ge sizes co espond o highe
maximum empe a u e o he hea ea men p ocedu e
(Table 1). Mo eo e , an inc ease o empe a u e causes
he g ow h o c ys alline phase con en ound om X- ay
di ac og ams. Sha p B agg e lec ions co espond o he
c ys alli es whe eas he smea ed ones come om he
amo phous ma ix. F om he ela i e con ibu ions o hese
wo componen s i is possible o es ima e a c ys alline
olume ic ac ion ( he me hod used e.g. in [4]). Howe e ,
he p ecision o his e alua ion is limi ed by he b oadening
o peaks because o he small g ain sizes and o he e ec s
[7]. On he basis o p ecisely de i ed uni cell cons an , he
silicon con en o g ains xSi was e alua ed. Fo all samples
xSi ≈ 18.5%, ha co esponds o diso de ed DO3 s uc u e.
In o de o examine he local p ope ies o in es iga ed
alloys, ansmission Mössbaue spec oscopy based on 57Fe
was employed. Room empe a u e measu emen s we e
pe o med using a s anda d spec ome e wi h a Co(Rh)
sou ce, in cons an accele a ion mode.
Hype ine ields
The Mössbaue spec um o he amo phous ibbon ha
makes a p ecu so o o he samples akes shape o
a b oadened Zeeman sex e ( ypical o such ma e ials)
wi h a nea ly symme ic single peak o hype ine ield dis-
ibu ion (HFD) and an a e age hype ine ield o abou
19.5 T. In he case o nanoc ys alline samples, complex
Mössbaue spec a a e obse ed, because o he coexis ence
o amo phous and c ys alline phases (Fig. 1). Addi ionally,
due o comp ising o silicon, which en e s in o he g ains,
he e a e se e al non-equi alen posi ions o i on a oms in
c ys alline encla es ep esen ed by a se o sha p sex e s in
he spec a. In almos all spec a he bes i was achie ed
using he con inuous (his og am-like) HFD o amo phous
emainde and i e sha p Zeeman sex e s (wi h hype ine
ields alues o 31.3−32.0 T, 30.2−31.0 T, 27.2−28.5 T,
24.1−24.2 T, 19.3−20.7 T), a ibu ed o he Fe-Si sys em
wi h DO3- ype s uc u e and con aining abou 18−19 a .%
o Si [2, 8]. Fi ing p ocedu e was pe o med wi h he
MOSFIT p og am [14]. A sligh e olu ion o he hype ine
Table 1. Samples cha -
ac e iza ion esul s om
X- ay di ac ome y and
TEM. D means an
a e age size o g ains, p
– pe cen age o c ys al-
line phase, xSi – silicon
con en o g ains.
Sample Annealing condi ions TEM X- ay di ac ome y
D (nm) D (nm) p (%) xSi (a .%)
1 as quenched − − 0 −
2↑200°C/min [600°C] ↓200°C/min ~7 5.2 ± 0.4 25.0 ± 0.8 18.6
3↑200°C/min [610°C] ↓200°C/min − 8.4 ± 0.2 38.2 ± 0.2 18.2
4↑200°C/min [620°C] ↓200°C/min −10.5 ± 0.1 51.7 ± 0.1 18.6
5↑200°C/min [630°C] ↓200°C/min ~10 10.0 ± 0.4 54.1 ± 0.1 18.6
6↑200°C/min [725°C] ↓200°C/min ~12 12.1 ± 0.1 73.1 ± 0.2 18.5
Fig. 1. Room empe a u e Mössbaue spec a o selec ed nanoc ys alline samples and subspec a ob ained by he i ing p ocedu e.
Hype ine ields and magne oelas ic su ace e ec s in Fe72Cu1.5Nb4Si13.5B9 nanoc ys alline alloy S87
ields was obse ed, inconsis en ly wi h X- ay di ac ion
esul s. No dis inc magne ic ex u e was ound.
F om he spec al a ea o he sex e s, he ela i e con en
o i on a oms in indi idual phases z was e alua ed. Depending
on he hea ea men condi ions, om 19 o 60 a .% o
i on a oms belong o c ys alline g ains. The co esponding
alues o olume ic ac ion o c ys alli es, p = z x/y, (x =
= 0.72, y = 0.815 − Fe a oms ac ion in ini ial ma e ial
and in c ys alli es, espec i ely) a e se e al a omic pe cen
smalle han ha de i ed om X- ay di ac ome y
(Table 2). The hype ine ield dis ibu ion ob ained o he
amo phous emainde shows a smea ed shape. In he case
o samples wi h he la ge con en o c ys alline phase, an
addi ional small maximum a abou 27.5 T is isible (Fig. 2)
ha could be a ibu ed o bounda y
(su ace) egions
be ween g ains and he es o sample. The
simila su ace
con ibu ion was obse ed in NANOPERM as epo ed in
se e al pape s, o ins ance [1, 6]. In he case o FINEMET
alloys, i is mo e di icul o dis inguish he in e acial
componen due o he p esence o Si in he c ys alli es and,
consequen ly, he complex s uc u e o Mössbaue spec a.
I would be easonable o conside also o he possible
sou ces o he high- ield componen in HFD – such as Nb-
o Cu- ich phases in he amo phous ma ix. Howe e , he
expec ed hype ine ield alues o hem a e a he low. The
p esence o magne os ic i e su ace e ec s (desc ibed in
he nex sec ion) is an addi ional a gumen o a ibu ing
he obse ed HFD componen o he su ace egions.
The sum p’ o in ensi y o he “su ace” componen pi
and he “c ys alline” one (p’ = p + pi) is in be e ag eemen
wi h X- ay esul s. The small disc epancies can be explained
by he di icul ies in sepa a ing o a disc e e componen
om he con inuous one in he Mössbaue spec a as well
as in di ac og ams. Taking in o accoun alues o p’, pi
and he a e age adius o g ains R, he wid h o in e aces
hi ≈ piR/3p was e alua ed (Table 2), which inc eases wi h
ising R and alls in he ange 0.2–0.5 nm. This means ha
one o wo a omic laye s a he bounda y o g ains belong
o he mixed phase, he p ope ies o which a e di e en
om hose o he c ys alline g ains and he amo phous
ma ix. The dissimila i ies in wid h o his a ea can be ela ed
o di e en hea ea men . Highe maximum empe a u e
and la ge hea ing a e a e p opi ious o he as e g ain
g ow h; a he same ime, because o he di e en s uc u e
and chemical con en o c ys alline and amo phous phases
as well as because o con ined di usion a e, his causes
a s onge dis inc ion be ween he amo phous ma ix and
b oade in e aces.
Magne os ic ion
In he case o nanoc ys alline sys ems ob ained by
con olled annealing o amo phous ibbons, he coexis ence
o c ys alline and amo phous phases plays an impo an
pa o he magne oelas ic beha io [5, 9, 10−13]. The model
p oposed by He ze o he e ec i e magne os ic ion
cons an λe in a wo-phase nanoc ys alline sys em [1],
based on he balance o he magne os ic ion be ween he
g ains and he esidual amo phous ma ix, p edic s he
linea dependence o λe on he olume ic ac ion o
c ys alline phase p. In classical nanoc ys alline FINEMET
and some NANOPERM alloys ( o ins ance FeZ B(Cu))
con ibu ions o igina ed om bo h phases ha e an opposi e
sign, so o a su icien ly la ge alue o p, he e ec i e
magne os ic ion cons an app oaches ze o. Signi ican
de ia ions om his simple model o e ec i e mag-
ne o
s ic ion a e obse ed in eal sys ems, which can be
explained
in con ex o wo di e en e ec s: (i) he
e olu ion o magne os ic i e p ope ies o amo phous
ma ix upon he c ys alliza ion p ocess, (ii) he con ibu ion
o c ys alli es su aces and in e aces o he e ec i e
magne os ic ion. Bo h e ec s a e included in he ollowing
ela ion [10−13]:
Table 2. Pe cen age o Mössbaue subspec a (indi idual Zeeman sex e s I−V, sum o sex e s z, sum
o sex e s and in e aces z’) and co esponding alues o : olume ic ac ion o c ys alli es p = z x/y,
(x = 0.72, y = 0.815), olume ic ac ion o c ys alli es + in e aces: p’ = z’ x/y, pe cen age pi and wid h
hi ≈ piR/3p o in e aces (R – a e age adius o g ains).
Zeeman sex e s con ibu ions (%) C ys alline ac ion (%) pi (%) hi (nm)
Sample I II III IV V zpz’p’
1−−−−− 0−−−−−
2 0.4 3.1 4.3 6.5 4.4 18.7 16.5 −−−−
3 5.0 4.4 5.7 8.6 7.7 31.4 27.7 −−−−
4 9.8 5.7 5.1 11.6 11.7 42.9 37.9 ~48 ~43 ~5 ~0.2
5 6.0 10.2 5.6 14.7 14.1 50.6 44.7 ~59 ~52 ~8 ~0.3
6 10.3 12.1 5.9 16.2 15.7 60.2 53.2 ~74 ~66 ~14 ~0.5
Fig. 2. A con inuous pa o hype ine ield dis ibu ion de i ed
o samples subjec ed o a ious kind o he hea ing p ocedu e
(see Table 1).
T. Szumia a e al.
S88
λe = pλc + (1 − p) (λ0
am + kp) + 3pλs /R,
whe e λc means c ys alli es magne os ic ion cons an , λs
− su ace cons an , λ0
am − amo phous ma ix cons an , k −
pa ame e o ma ix magne os ic ion e olu ion, R − a e -
age adius o g ains.
Magne oelas ic p ope ies we e examined using
a SMFMR echnique (s ain-modula ed e omagne ic
esonance). FONER- ype magne ome y esul s showed
ha esonan ield o he o de o 0.1 T, used o SMFMR
expe imen , is su icien o sa u a e a magne iza ion, so
sa u a ion magne os ic ion cons an was measu ed. On he
basis o abo e dependence, he esul s we e i ed by wo
means (Fig. 3): (i) he e ec i e sa u a ion magne os ic ion
cons an λ
e
was analyzed as a unc ion o c ys alline ac ion
p; a cons an , a e age adius R = <R> = 4.6 nm o
nanoc ys alli es was assumed, (ii) λe (p, R) was i ed as
a unc ion o wo a iables p, R. In bo h cases, we used
λc = −6.8 ppm, he alue cha ac e is ic o polyc ys alline
Fe71.5Si18.5 alloys; λs, λ0
am and k we e i ing pa ame e s. The
ob ained esul s, collec ed in Table 3, poin o he p esence
o signi ican su ace e ec s in he g ains − he alue o
a e age su ace magne os ic ion cons an λs ≈ 8.5 ppm.nm
(which is posi i e, as o he amo phous esidue) is abou
50% highe han in classical FINEMET [10, 12]. Mo eo e ,
some a gumen s we e ound, which suppo he su ace
magne os ic ion cons an e olu ion when changing
he annealing condi ions and, consequen ly, he size o
nanoc ys alli es. Besides, he s ong dec ease o he
amo phous ma ix magne os ic ion in he cou se o c ys-
alliza ion is con i med, because o he signi ican alue o
k = −19.4 ppm.
Conclusions
The non-iso he mal annealing p ocedu e and highe − han
in classical FINEMET − niobium con en enabled he
e ec i e p oduc ion o small c ys alli es o di e en sizes
on a nanome e scale. The analysis o Mössbaue spec a
con i med he coexis ence o bo h he DO3- ype c ys alline
phase and he amo phous one. Besides, an addi ional
maximum in he hype ine ield dis ibu ion is a ibu ed
o su ace and in e ace egions, which occu a he bound-
a ies o g ains. Likewise, su ace e ec s a e e idenced on
he basis o magne os ic ion in es iga ion. The a e age
alue o he su ace magne os ic ion cons an is abou 50%
la ge han in classical FINEMET and seems o be
dependen on hea ea men condi ions. In addi ion, a s ong
e olu ion o magne os ic ion cons an o amo phous
ma ix was obse ed.
Re e ences
1. B zózka K, Ślawska-Waniewska A, Nowicki P, Jezui a K
(1997) Hype ine magne ic ields in FeZ B(Cu) alloys. Ma e
Sci Eng A 226/228:654−658
2. Häggs öm L, G ánäs L, Wäppling R, De ana ayanan S
(1973) Mössbaue s udy o o de ing in FeSi alloys. Phys
Sc ip a 7:125−131
3. He ze G (1993) Nanoc ys alline so magne ic ma e ials.
Phys Sc ip a T 49:307−314
4. Kulik T (1998) Annealing empe a u e dependence o size,
mo phology and composi ion o p ima y c ys als c ea ed in
Fe76.5Cu1Si13.5B9 glass. Ma e Sci Fo um 269/272:707−712
5. Kulik T, He nando A (1996) Magne oelas ic p ope ies o
Fe76.5−xCuxNbSi13.5B9 alloys nanoc ys allized om amo phous
s a e. J Magn Magn Ma e 160:269−270
6. Miglie ini M, G enèche JM (1997) Mössbaue spec ome y
o Fe(Cu)MB- ype nanoc ys alline alloys: II. The opog aphy
o hype ine in e ac ions in Fe(Cu)Z B alloys. J Phys-
Condens Ma e 9:2321−2347
7. Miglie ini M, G enèche JM (1999) Mössbaue spec ome y
applied o i on-based nanoc ys alline alloys II. In: Miglie ini
M, Pe idis D (eds) Mössbaue spec oscopy in ma e ials
science. Kluwe , Ne he lands, pp 257−272
8. S ea ns MB (1963) In e nal magne ic ields, isome shi s and
ela i e abundances o he a ious Fe si es in FeSi alloys.
Phys Re 129:1136−1144
9. Szumia a T, B zózka K, Gaw oński M e al. (2000) Mössbaue
and magne os ic ion s udies o c ys alliza ion p ocess in
FeCuSiB alloy. Molecula Physics Repo s 30:159−166
10. Ślawska-Waniewska A, Roig A, Molins E, G enèche J-M,
Żube ek R (1997) Su ace e ec s in Fe-based nanoc ys alline
alloys. J Appl Phys 81;8:4652−4654
11. Ślawska-Waniewska A, Żube ek R (1998) Su ace magne o-
s ic ion in nanoc ys alline magne s. Elec on Technology
31;1:29−32
12. Ślawska-Waniewska A, Żube ek R, González J, Szymczak
H (1997) On he magne os ic ion in Fe-based nanoc ys alline
alloys − su ace and bulk con ibu ions. In: Duhaj P, M a ko
P, S ec P (eds) Rapidly quenched and me as able ma e ials.
P oceedings. Else ie , Ams e dam, pp 220−223
13. Ślawska-Waniewska A, Żube ek R, Nowicki P (1996)
Sa u a ion magne os ic ion o FeZ B(Cu) nanoc ys alline
alloys. J Magn Magn Ma e 157/158:147−148
14. Teille J, Va e F (1986) MOSFIT p og am
15. Yoshizawa Y, Oguma S, Yamauchi K (1988) New Fe-based
so magne ic alloys composed o ul a ine g ain s uc u e. J
Appl Phys 64:6044−6046
Table 3. Values o pa ame e s (
λ
0
am, k and
λ
s – see ex ) ob ained
om i ing o he e ec i e magne os ic ion cons an o
Fe72Cu1.5Nb4Si13.5B9 (see ex ).
Fe72Cu1.5Nb4Si13.5B9
λ
c
λ
0
am k
λ
s
(ppm) (ppm) (ppm) (ppm.nm)
Dependence:
λ
e (p)|R = 4.6 nm −6.8 28.1 −19.4 8.5
Dependence:
λ
e (p, R) −6.8 27.8 −19.4 8.9
Fig. 3. E ec i e sa u a ion magne os ic ion cons an plo ed wi h
c ys alline ac ion ob ained by X- ay spec ome y.