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Anomalous temperature dependence of magnetization in amorphous (Fe0.1Ni0.9)77Si10B13 alloy
Journal of Magnetism and Magnetic Matermls 31-34 (1983) 1399-1400 ANOMALOUS
TEMPERATURE
DEPENDENCE
1399 OF
MAGNETIZATION
IN AMORPHOUS
(Feo t N i 0 9) 77S i i0 B 13 A L L O Y M. T A K A H A S H I ,
I. O K A M O T O
a n d T. M I Y A Z A K I
Department of Apphed Physics, Tohoku Umverstty, Sendat 980, Japan
The temperature and magnetic field dependence of dc magneozatlon o and ac susceptlbd~ty X,,~ were investigated for an amorphous (Fe 0 iNlo9)77SlloBi3 alloy to clarify the ongm of the mflectmn of X,,, vs T curves observed at low temperatures The results are d~scussed based upon the magnenc cluster model
Recently, m u c h interest has been paid to a m o r p h o u s spin-glass ferromagnetism [1-4] as well as to the spinglass of crystalhne A u - F e [5] and P d - F e - M n [6] alloys. However, tt seems that there are some ambiguous interpretations of the lnflectmn or cusp observed m the t e m p e r a t u r e d e p e n d e n c e of ac susceptibility for the a m o r p h o u s spin-glass Furthermore, no convincing picture of the spin-glass in a m o r p h o u s alloys has been proposed. A m o r p h o u s (Fe 1 x N I ~ ) v v S I I o B I 3 ( 0 ~ x _< 0 9) alloys exhibit ferromagnetic characters and their Curie temperature decreases with increasing x [7], while NiTvSimBi3 alloy ( x = 1 0) exhibits Pauh para-type m a g n e t i s m [8] Furthermore, spm-glass-hke magnetic properties are reported for the alloy with x > 0 8 [41 The present paper describes the dc magnetization o and ac s u s c e p U b t h t y Xd~ of a m o r p h o u s (Fe01Ni09)7vSll0Bl~ alloy measured in various mag-
netlc fields in the temperature range 4 2 90 K, and discussion is made on the origin of the inflection observed in the Xac-T curve. The samples for the m e a s u r e m e n t of o were formed into a toroldal by winding an a m o r p h o u s ribbon of 7 m in length, of which insulation was made using AI203 p o w d e r The dc magnetization was measured using a dc hysteresis loop tracer. The ribbons, 6 cm in length, were loaded into a pyrex sample holder and the ac susceptlblhty was measured by using a H a r t s h o r n Bridge type a p p a r a t u s The n u m b e r of w m d m g s on the primary and secondary coils were 5500 a n d 4450 turns, respectwely, and drivmg fields up to 34 Oe were operated at 110 Hz In fig 1 the temperature dependence of o, the coercive force a n d hysteresis loops at specified temperatures are shown Solid points m the figure exhibit the values r
r
[ IOe)
F
17
B
[
r
i
60
70
80
Th
0 io~
2(
. \
Tf
g6
t~
a~ v
i
034
x~
I00
I
>g4
b o 5O x
L
1
I:~
20
30
~-0
.50
6Q
70
BO
90
0
0
iO
20
30
40
50
T(K/
T(K)
Fig 1 Temperature dependence of dc magnetization for an amorphous (Fe 0 iNlog)77SlloB13 alloy 0304-8853/83/0000-0000/$03
2
O0 © 1983 N o r t h - H o l l a n d
Fig 2 Temperature dependence of ac suscepnbdlty for an amorphous (Fe 0 iNlo9)77SlloB13 alloy
M Fal.ahag'h, et al / Magnet~zatton m arnmphou* (t-e./A't. v)--~,*/.B/¢ allm
1400
l
lcy 2
I r-,
T~ TI
#
b Th
60
5O 4 0 ",c
r o'
2 ~"~
3 <) ~-
Tf
- -o-o-
2P
Fig 4 Schematic representanon~ of dc nlagnenzatJon and a~`,uscepnbflJty ---X (cluster), X (matrix)
12'
I i
I(~
L
__L
2~
30
0
;, ' Oe ',
Fig 3 Magnenc field dependences of X,,. (around Tf and T~,) and the value., of Tf and 7"h
o f o at t h e s a m e m e a s u r i n g field o b t a i n e d after o n c e b e i n g s a t u r a t e d the m a g n e U z a n o n C h a r a c t e n s n c features o f t h e s e t e m p e r a t u r e d e p e n d e n c e s are as follows (1) A h y s t e r e s i s loop with coercive force ( 2 - 8 5 Oe) is o b s e r v e d below a b o u t 20 K It is q m t e s l m d a r to t h o s e of f e r r o m a g n e t s a n d n o t s p e c m l to the a m o r p h o u s spinglass state (2) T h e o vs T c u r v e e x h i b i t s a b r o a d m a x m m m at 7.1 a n d a n m f l e c t l o n at 7".2 In fig 2 the t e m p e r a t u r e d e p e n d e n c e of X.~ m e a s u r e d Ln fields up to 34 O e IS s h o w n W h e n fields are b e l o w 1 7 0 e , m f l e c n o n s are clearly o b s e r v e d at T t a n d F h H o w e v e r . they b e c o m e r o u n d e d with m c r e a s m g fields In o r d e r to e x a m m e t h e o n g m o f the reflection at 7], the m a g n e t i c field d e p e n d e n c e of X,~ a r o u n d T r is c o m p a r e d with t h a t a r o u n d T h T h e result is s h o w n m fig 3 t o g e t h e r with the field d e p e n d e n c e of 7} a n d T h A s ~een 111 the figure, X,,~ m e a s u r e d at b o t h t e m p e r a t u r e s exh~btts a m a x i m u m a n d d e c r e a s e s following the relanons, X,,jatT f ) o : ,~ os,~ a n d X,,~(at ~ T h ) 0 ( /~ o ~ T h e m a x i m u m s h i f t s to h i g h e r m a g n e n c field with lowering the t e m p e r a t u r e T h e reflection p o i n t s , T r a n d T h, also d e c r e a s e with i n c r e a s i n g field a n d t h e r e is no difference between them I o e x p l a i n t h e c h a r a c t e n q l c f e a t u r e s of t h e t e m p e r a ture d e p e n d e n c e of o a n d X.,,. we p r o p o s e that m a g n e u c cluster`, w~th a C u r i e t e m p e r a t u r e lower t h a n that of a l e r r o m a g n e n c m a t r i x exist m s a m p l e s A s s u m i n g that t h e f e r r o m a g n e u c m a t r i x feels a large m a g n e t t c a n l s o t -
r o p y by lowering t e m p e r a t u r e , we c a n e x p l a i n the temp e r a t u r e d e p e n d e n c e s of o a n d X ~ s e l f - c o n s i s t e n t l y 11 t h e alloy ~s h o m o g e n e o u s , o s h o u l d d e c r e a s e m o n o t o m cally with i n c r e a s i n g t e m p e r a t u r e H o w e v e r , it follows. as is the case, the c u r v e O A B C D exhlbltung a b r o a d m a x i m u m as s h o w n m fig 4 d u e to the c o e x i s t e n c e ot t h e m a g n e t i c c l u s t e r s a n d t h e i n c r e a s e of c o e r c w e forcc b> l o w e r i n g t e m p e r a t u r e T h e m e a s u r e d v a l u e of X,,~ ma> be c o n s M e r e d ,t`, given b,, t h e s u m of X (cluster) a n d X ( m a t r i x ) a`, s c h e m a n c a l l ~ s h o w n m fig 4 T h e m f t e c n o n at 7 t J`, u s u a l l y i n t e r p r e t e d as b e i n g c a u s e d b> the t r a n ` , m o n b e t w e e e n s p i n - g l a s s a n d f e r r o m a g n e m , states H o w e v e r , it is also p o s s i b l e to m t e r p r e t e T r as a f e r r o m a g n e n c C t m e t e m p e r a t u r e of the d u s t e r , since the m a g n e n ~ field d e p e n d e n c e of the reflection is e n n r e l y a n a l o g o u s to that of H o p k m s o n peak F o r f u r t h e r u n d e r q a n d l n g ol the origin of lj ex. m m l , m o n s o f the m a g n e n c field c o o h n g a n d a n n e a h n g effects on Tf a n d electrical res~sn,,~t\, are n o w m prog r e s s T h e d a t a will be & s c u s s e d e l s e w h e r e
Reference,, [I] T MlzoguchL T R McGmre, S Kirkpatru_k and R I Gambmo, Phys Re~ I_ett 38 (1977) 89 [2] J ' I Prater and I Egaml J Appl P h p 50II979) 17(16 [3] J A Geohegan and S M Bhagat J Magn Magn Mat 25 (1981) 17 [4] (; Hdscher, R Haferl 1t K~rchmayr, M Muller and tt I (]unlherodt, J Phy`, F I1 (1981)2429 [51 V Cannella and I A Mydo`,h, Phvs Rev B 6 (197214220 [6] B i t Verbeck, G J Nleuwenhuvs H Stocker ,rod IA Mydosh. Phys Rev Len 40 (1978) 586 [7] M Goto, l ]okunaga H T a n g e a n d T tlamatake, Jpn I &ppl Phys 19 (1980) 51 [81 M Fakahashland M KashHnura u n p u b h q m d
TEMPERATURE
DEPENDENCE
1399 OF
MAGNETIZATION
IN AMORPHOUS
(Feo t N i 0 9) 77S i i0 B 13 A L L O Y M. T A K A H A S H I ,
I. O K A M O T O
a n d T. M I Y A Z A K I
Department of Apphed Physics, Tohoku Umverstty, Sendat 980, Japan
The temperature and magnetic field dependence of dc magneozatlon o and ac susceptlbd~ty X,,~ were investigated for an amorphous (Fe 0 iNlo9)77SlloBi3 alloy to clarify the ongm of the mflectmn of X,,, vs T curves observed at low temperatures The results are d~scussed based upon the magnenc cluster model
Recently, m u c h interest has been paid to a m o r p h o u s spin-glass ferromagnetism [1-4] as well as to the spinglass of crystalhne A u - F e [5] and P d - F e - M n [6] alloys. However, tt seems that there are some ambiguous interpretations of the lnflectmn or cusp observed m the t e m p e r a t u r e d e p e n d e n c e of ac susceptibility for the a m o r p h o u s spin-glass Furthermore, no convincing picture of the spin-glass in a m o r p h o u s alloys has been proposed. A m o r p h o u s (Fe 1 x N I ~ ) v v S I I o B I 3 ( 0 ~ x _< 0 9) alloys exhibit ferromagnetic characters and their Curie temperature decreases with increasing x [7], while NiTvSimBi3 alloy ( x = 1 0) exhibits Pauh para-type m a g n e t i s m [8] Furthermore, spm-glass-hke magnetic properties are reported for the alloy with x > 0 8 [41 The present paper describes the dc magnetization o and ac s u s c e p U b t h t y Xd~ of a m o r p h o u s (Fe01Ni09)7vSll0Bl~ alloy measured in various mag-
netlc fields in the temperature range 4 2 90 K, and discussion is made on the origin of the inflection observed in the Xac-T curve. The samples for the m e a s u r e m e n t of o were formed into a toroldal by winding an a m o r p h o u s ribbon of 7 m in length, of which insulation was made using AI203 p o w d e r The dc magnetization was measured using a dc hysteresis loop tracer. The ribbons, 6 cm in length, were loaded into a pyrex sample holder and the ac susceptlblhty was measured by using a H a r t s h o r n Bridge type a p p a r a t u s The n u m b e r of w m d m g s on the primary and secondary coils were 5500 a n d 4450 turns, respectwely, and drivmg fields up to 34 Oe were operated at 110 Hz In fig 1 the temperature dependence of o, the coercive force a n d hysteresis loops at specified temperatures are shown Solid points m the figure exhibit the values r
r
[ IOe)
F
17
B
[
r
i
60
70
80
Th
0 io~
2(
. \
Tf
g6
t~
a~ v
i
034
x~
I00
I
>g4
b o 5O x
L
1
I:~
20
30
~-0
.50
6Q
70
BO
90
0
0
iO
20
30
40
50
T(K/
T(K)
Fig 1 Temperature dependence of dc magnetization for an amorphous (Fe 0 iNlog)77SlloB13 alloy 0304-8853/83/0000-0000/$03
2
O0 © 1983 N o r t h - H o l l a n d
Fig 2 Temperature dependence of ac suscepnbdlty for an amorphous (Fe 0 iNlo9)77SlloB13 alloy
M Fal.ahag'h, et al / Magnet~zatton m arnmphou* (t-e./A't. v)--~,*/.B/¢ allm
1400
l
lcy 2
I r-,
T~ TI
#
b Th
60
5O 4 0 ",c
r o'
2 ~"~
3 <) ~-
Tf
- -o-o-
2P
Fig 4 Schematic representanon~ of dc nlagnenzatJon and a~`,uscepnbflJty ---X (cluster), X (matrix)
12'
I i
I(~
L
__L
2~
30
0
;, ' Oe ',
Fig 3 Magnenc field dependences of X,,. (around Tf and T~,) and the value., of Tf and 7"h
o f o at t h e s a m e m e a s u r i n g field o b t a i n e d after o n c e b e i n g s a t u r a t e d the m a g n e U z a n o n C h a r a c t e n s n c features o f t h e s e t e m p e r a t u r e d e p e n d e n c e s are as follows (1) A h y s t e r e s i s loop with coercive force ( 2 - 8 5 Oe) is o b s e r v e d below a b o u t 20 K It is q m t e s l m d a r to t h o s e of f e r r o m a g n e t s a n d n o t s p e c m l to the a m o r p h o u s spinglass state (2) T h e o vs T c u r v e e x h i b i t s a b r o a d m a x m m m at 7.1 a n d a n m f l e c t l o n at 7".2 In fig 2 the t e m p e r a t u r e d e p e n d e n c e of X.~ m e a s u r e d Ln fields up to 34 O e IS s h o w n W h e n fields are b e l o w 1 7 0 e , m f l e c n o n s are clearly o b s e r v e d at T t a n d F h H o w e v e r . they b e c o m e r o u n d e d with m c r e a s m g fields In o r d e r to e x a m m e t h e o n g m o f the reflection at 7], the m a g n e t i c field d e p e n d e n c e of X,~ a r o u n d T r is c o m p a r e d with t h a t a r o u n d T h T h e result is s h o w n m fig 3 t o g e t h e r with the field d e p e n d e n c e of 7} a n d T h A s ~een 111 the figure, X,,~ m e a s u r e d at b o t h t e m p e r a t u r e s exh~btts a m a x i m u m a n d d e c r e a s e s following the relanons, X,,jatT f ) o : ,~ os,~ a n d X,,~(at ~ T h ) 0 ( /~ o ~ T h e m a x i m u m s h i f t s to h i g h e r m a g n e n c field with lowering the t e m p e r a t u r e T h e reflection p o i n t s , T r a n d T h, also d e c r e a s e with i n c r e a s i n g field a n d t h e r e is no difference between them I o e x p l a i n t h e c h a r a c t e n q l c f e a t u r e s of t h e t e m p e r a ture d e p e n d e n c e of o a n d X.,,. we p r o p o s e that m a g n e u c cluster`, w~th a C u r i e t e m p e r a t u r e lower t h a n that of a l e r r o m a g n e n c m a t r i x exist m s a m p l e s A s s u m i n g that t h e f e r r o m a g n e u c m a t r i x feels a large m a g n e t t c a n l s o t -
r o p y by lowering t e m p e r a t u r e , we c a n e x p l a i n the temp e r a t u r e d e p e n d e n c e s of o a n d X ~ s e l f - c o n s i s t e n t l y 11 t h e alloy ~s h o m o g e n e o u s , o s h o u l d d e c r e a s e m o n o t o m cally with i n c r e a s i n g t e m p e r a t u r e H o w e v e r , it follows. as is the case, the c u r v e O A B C D exhlbltung a b r o a d m a x i m u m as s h o w n m fig 4 d u e to the c o e x i s t e n c e ot t h e m a g n e t i c c l u s t e r s a n d t h e i n c r e a s e of c o e r c w e forcc b> l o w e r i n g t e m p e r a t u r e T h e m e a s u r e d v a l u e of X,,~ ma> be c o n s M e r e d ,t`, given b,, t h e s u m of X (cluster) a n d X ( m a t r i x ) a`, s c h e m a n c a l l ~ s h o w n m fig 4 T h e m f t e c n o n at 7 t J`, u s u a l l y i n t e r p r e t e d as b e i n g c a u s e d b> the t r a n ` , m o n b e t w e e e n s p i n - g l a s s a n d f e r r o m a g n e m , states H o w e v e r , it is also p o s s i b l e to m t e r p r e t e T r as a f e r r o m a g n e n c C t m e t e m p e r a t u r e of the d u s t e r , since the m a g n e n ~ field d e p e n d e n c e of the reflection is e n n r e l y a n a l o g o u s to that of H o p k m s o n peak F o r f u r t h e r u n d e r q a n d l n g ol the origin of lj ex. m m l , m o n s o f the m a g n e n c field c o o h n g a n d a n n e a h n g effects on Tf a n d electrical res~sn,,~t\, are n o w m prog r e s s T h e d a t a will be & s c u s s e d e l s e w h e r e
Reference,, [I] T MlzoguchL T R McGmre, S Kirkpatru_k and R I Gambmo, Phys Re~ I_ett 38 (1977) 89 [2] J ' I Prater and I Egaml J Appl P h p 50II979) 17(16 [3] J A Geohegan and S M Bhagat J Magn Magn Mat 25 (1981) 17 [4] (; Hdscher, R Haferl 1t K~rchmayr, M Muller and tt I (]unlherodt, J Phy`, F I1 (1981)2429 [51 V Cannella and I A Mydo`,h, Phvs Rev B 6 (197214220 [6] B i t Verbeck, G J Nleuwenhuvs H Stocker ,rod IA Mydosh. Phys Rev Len 40 (1978) 586 [7] M Goto, l ]okunaga H T a n g e a n d T tlamatake, Jpn I &ppl Phys 19 (1980) 51 [81 M Fakahashland M KashHnura u n p u b h q m d