Effect of substitution of 3d metals for Cu in Bi2(Sr0.6Ca0.4)3Cu2Oy

Physica C 162-164 ( 1989 ) 981-982 North-Holland

Effect of Substitution of 3d Metals for Cu in Bi2(Sro.6Cao.4)3CU2Oy

Kunimitsu UCHINOKURA, Tomoaki YABE, Seiki TAKEBAYASHI, Hasashi HASE and Atsutaka RAEDA Department of Applied Physics, The University of Tokyo, 7-3-1Hongo,

Bunkyo-ku, Tokyo 113, Japan

The effect of the substitution of 3d metals (Fe, Co, Hi and Zn) for Cu was investigated. Lattice constants, DC resistivity, Hall effect, magnetic susceptibilities in normal and superconducting phases were measured. The change of the Hall coefficient with the substitution was much smaller than those in YBa2Cu30. or in Y or lanthanide substituted Bi2(Sr, Ca)3Cu20.. The change of T c with the substltutlon of Fe, Co, NI with localized magnetic moment did not differ much from that of Zn with no magnetic moment.

In

the

LnBa2Cu3Oy nides)

copper-oxide

based

superconductors

system (Ln=Y or some of the

lantha-

many works have been done on the

effect

of the substitution by impurities on the

physi-

cal properties. of

In particular, the substitution

3d metals for Cu is expected to provide

im"-

portant information on the pairing mechanism

of

high-temperature

In

YBa2Cu3Oy, large most

superconductivity.

however, the substitution induces

change of the carrier density,

which

probably due to the existence of

the

chain.

Furthermore, the existence of two

of Cu sites makes the problem more In the

is CuO

kinds

complicated.

this paper, we shall present the results experiments on the effect of the

tion of 3d metals for Cu in

a

of

substitu-

c e e d s t h e v a l u e s g i v e n above, d i f f r a c t i o n

The measurements o f t h e m a g n e t i c s u s c e p t i b i l ity

below and n e a r Tc show t h a t t h e

temperature which

the

decreases phase

the previous work I it was

revealed

the superconducting 80-K phase of

study.

Bi-Sr-Ca-Cu-O

solid solution.

The samples

Zn

The

conventional X-ray

of

single-phase x=O.06 x=0.O15

for

solid-state

powder

diffraction

samples Fe

can

the absolute

and a l s o f o r t h e Cu

appear)

the

single-

value

of

the

In F i g . 1 T c

deficient

Bi2(Sro.6Ca0.4)3(CUl_x[~ x)20y It

([~=Cu

vs

samples vacancy).

shows t h a t t h e r e i s no p r o m i n e n t

difference

among t h e d e c r e a s e s o f Tc w i t h x f o r a l l o f

the

3d m e t a l s u s e d ,

The

8O

in t h e s i n g l e - p h a s e r e g i o n .

be

substitution,

t

substitu-

method.

revealed obtained x=0.10 When

that up

A

,

i

• o

•

•

0

AA~

R

• M=Co

-'~ 40

o M=bJ , M=Zn

prepared

reaction

i

o

o undoped =M=[] o M=Fe

in

Bi2(Sr0.6Ca0.4) 3-

for Ni and x=O.01 for Zn.

6o

i.

Therefore

for the

(CU1_xHx)2Oy (H=Fe, Co, Ni or Zn) were in

and

at

to

x i s shown f o r t h e s a m p l e s doped w i t h Fe, Co, Ni and

that

can be obtained most easily at z=0.4

we used Bi2(Sr0.6Ca0.4)3CU2Oy tion

p r o g r e s s i v e l y w i t h x in

region

lent Cu site (neglecting superlattice) and whose

Bi2(Srl_zCaz)3CU2Oy

temperature

begins

Meissner signal also decreases.

oxygen content does not change much.

system

Tc ( d e f i n e d by t h e Meissner signal

transition

Bi2(Sr1_zCaz)3CU2Oy

(Tc=80 K phase), which contains only one equiva-

In

peaks

of the impurity phases appears.

30

m

0

I

4 No~r~l

I

6 X

I

8 (%)

I

10

to

for

Co,

x

ex-

0921-4534/89/$03.50 © Elsevier Science Publishers B.V. (North-Holland)

FIGURE 1 Critical temperatures vs x in Bi2(Sr 0 6Cao 4)3 (CU1_xHx)2Oy (H=Fe, Co, Hi, Zn or-[~) . . . . .

K. Uchinokura et al. / Effect of substitution o f 3d metals for Cu

982

results

the

of

consistent bility

resistivity

measurements

with those of the magnetic

measurements.

Moreover

Ca0.4)3(CUl_x[]x)2Oy, slightly.

Tc

are

for

B i 2 ( S r o . 6-

changes

3

I

only

very

T h i s may s u g g e s t t h a t t h e change

I

1

suscepti-

I

I

T=3OOK

I

M=Fe • M=Co o

(3

o r)

o undoped

E 02

of o

Tc i s n o t due t o t h e d e f i c i e n c y o f Cu b u t r e a l l y due t o t h e s u b s t i t u t i o n The

magnetic

Cao.4)3(CUl_xMx)2Oy state

clearly

o f 3d m e t a l s f o r Cu.

susceptibility (M=Fe,

in

B i 2 ( S r o . 6-

Co) in

the

normal

shows t h e e x i s t e n c e o f l o c a l

magmB

netic

moments.

bility

We assumed t h a t

the

X (T) can be e x p r e s s e d a s :

where C=Np~ff~ ~ / ( 3 k B ) ,

X ( T ) = x 0+C/T,

X 0 is the

Then we o b t a i n e d t h e

effective

Bohr magneton p e f f = 3 . 6 f o r b o t h Fe and Co in t h e single-phase

samples.

behavior

the

of

For Ni-doped sample

normal-state

Fe

or

is

Co, but t h e x r e g i o n o f t h e s i n g l e - p h a s e much l i m i t e d t o o b t a i n P e f f "

hand,

the

different

effect

On t h e

o f Zn s u b s t i t u t i o n

from o t h e r s .

other

is

quite

With t h e Zn s u b s t i t u t i o n

the

normal-state susceptibility

and

i t r a t h e r t e n d s t o d e c r e a s e w i t h x in

gle-phase

samples.

barely

T h e r e f o r e we

that the substituted

changes

may

sin-

conclude

Fe, Co o r Ni ion r e a l l y has

localized magnetic moment and Zn ion is

nonmag-

6 X

8

10

(%1

FIGURE 2 The dependence of Hall coefficient on x Bi2(Sro.6Cao.4)3(CUl_xMx)2Oy (~=Fe and Co)

in

stitution The

in t h i s s y s t e m . experimental

susceptibility that

results

two

the

in t h e normal s t a t e

the magnetic s t a t e s

the

of

groups;

magnetic

clearly

are different

shows

between

(Fe, Co, Hi) and Zn.

On

the

o t h e r hand t h e d e c r e a s e o f Tc w i t h t h e s u b s t i t u tion in

i s a l m o s t t h e same between t h e two the single-phase region.

the

possibility

caused effect

that

This

may

the decrease

s o l e l y by t h e s i m p l e

of

magnetic

groups exclude Tc

is

impurity

p r o p o s e d by Abrikosov and Gorkov 4 f o r t h e

BCS-type s u p e r c o n d u c t o r s .

netic. Figure 2 shows the x dependence of Hall coef-

These

results

ficient R H in Bi2(Sr0.6Cao.4)3(CUl_xHx)2Oy

(M=Fe

CU2Oy

and Co).

small

investigation

The change of R H with x is very

and much smaller than that in YBa2CU30y 2 and Ln

I

4 Nominal

the

susceptibility

seems t h e same a s f o r t h e s a m p l e s c o n t a i n i n g

too

I

2

temperature-

i n d e p e n d e n t term, N i s t h e number d e n s i t y o f t h e i m p u r i t y atoms.

I

0

suscepti-

substituted Bi2(Sr,Ca)3CU2Oy. 3

This

in

holds

metal

indicate that

i s more s u i t a b l e of

substitution

B i 2 ( S r l _ z C a z ) 3-

t h a n YBa2CU3Oy f o r

the direct

e f f e c t of

f o r Cu in h i g h - T c

the

the 3d

supercon-

ductors.

also in the substitution of Ni and Zn. In

YBa2CU3Oy,

owing to

the

induced

large

change in carrier density, we cannot tell whether

the change of the physical properties,

e.g.

Tc, is the direct effect of the substitution is

caused indirectly through the change of

carrier small

density. change

of

The experimental carrier

(Sr0.6Cao.4)3(CUl_xMx)2Oy bility

density provides

result in the

to reveal the direct effect of the

or the of Bi 2-

possisub-

References I. A. Maeda, T. Yabe, H. Ikuta, Y. Nakayama, Wada, S. Okuda, T. Ito, M. Izumi, Uchinokura, S. Uchida and S. Tanaka, Jpn. Appl. Phys. 27 (1988) L661.

T. K. J.

2. N. Okazaki et a l . , p r e p r i n t . 3. T. Tamegai et al., Jpn. J. Appl. Phys. (1989) Lll2. 4. For example, A.A. Abrikosov and L.P. Soy. Phys. JETP 12 (1961) 1243.

Gorkov,