Films of YBa2Cu3O7-x were grown on (100) cubic zirconia with 8 percent yttria by laser ablation from sintered targets of YBa2Cu3O7-x. The temperature of the zirconia substrate during growth was varied between 700 and 780 C. The atmosphere during growth was 170 mtorr of O2. The films were subsequently slowly cooled in-situ in 1 atm of O2. The best films were c-axis aligned and had a transition temperature of 87.7 K. The superconducting transition temperature and the X-ray diffraction analysis is reported as a function of the substrate temperature and of the angle between the laser beam and the target's normal

Jenkins, Kimberly A.

Meola, Joseph E.

Warner, Joseph D.

English

NASA Technical Reports Server

LNASA Technical Memorandum 102350
Study of Deposition of YBa2Cu307_ x
On Cubic Zirc0nia
Joseph D, Warner and Joseph E. Meo!a
Lewis Research Center
Cleveland, Ohio
and
Kimberly A. Jenkins
Ohio University
AthenL Ohio
(NA'_ A-T,U--- 102350 ) 3TUOY
Y_d?Cu._q7-x ON CuD, IC
O_ _EPUSITI_N UF
ZIRCqNIA (NASA) 7 D
CSCL ZOL
G3/76
Prepared for the
Third Annual Conference on Superconductivity and Applications
sponsored by The New York State Institute on Superconductivity
Buffalo, New York, September 19-21, 1989
NO0-107_7
Unclas
N/ A
https://ntrs.nasa.gov/search.jsp?R=19900001421 2020-03-20T01:03:21+00:00Z

STUDY OF DEPOSITION OF YBa2Cu307_ x ON CUBIC ZIRCONIA
o%
tO
O
ko Joseph D. Warner and Joseph E. Meola
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio 44135
Kimberly A. Jenkins*
Ohio University
Athens, Ohio &5701
ABSTRACT
Films of YBa2Cu3OT_ x have been grown on (i00) cubic zirconia with
8 percent yttria by laser ablation from sintered targets of YBa2Cu307_ x.
The temperature of the zirconia substrate during growth was varied
between 700 and 780 °C. The atmosphere during growth was 170 mtorr of
oxygen. The films were subsequently slowly cooled [n-situ in i aim of
oxygen. The best films were c-axis aligned and had a transition tem-
perature of 87.7 K. The superconducting transition temperature and the
x-ray diffraction analysis will be reported as a function of the sub-
strate temperature and of the angle between the laser beam and the
target's normal.
INTRODUCTION
Laser ablation of high temperature superconductin_ (HTS) thin films
has been shown to give high-quality films on SrTi03 .I-° For microwave
applications, however, a high-quality film is not enough. The substrate
must also have low losses. Unfortunately, SrTiO 3 does not have low
microwave losses. Therefore, in investigating HTS films for microwave
applications, we have chosen as a substrate cubic zirconia stabilized
with 8 percent yttria. It has a real dielectric constant of 25.4 and an
imaginary dielectric constant of 1.74 at 33 GHz. 7 This is suitable for
many microwave applications for space communications.
EXPERIMENTAL PROCEDURE
The laser ablation technique is similar to that which other
researchers have used. 1-6 The details of the geometry are show_ in
Fig. I. The substrates used were polished (I00) cubic zirconia obtained
from Atomergic Corporation. The samples were degreased in acetone and
methanol prior to being glued with silver paint to the stainless steel
sample holder. The paint was cured at 200 °C for 15 min in air and
*Summer Intern at NASA Lewis.
VACUUMCHARBER!
Po2 = 170 MILLITORR
!
HEATED SAMPLE
FIGURE I, - SCHEMATIC OF LASER ABLATION
EXP[RIf'£NT.
allowed to cool before being placed in the vacuum chamber. The chamber
was evacuated to 2x10 -7 torr or less using a liquid nitrogen cold trapped
diffusion pump before the sample was warmed to 500 °C within 30 min. A
continuous flow of oxygen (120 sccm) was then introduced into the cham-
ber, and the sample was heated to its final temperature using resistive
heating. The temperature was measured by a type K thermocouple that was
welded to the stainless plate. The samples were within 5 mm of the ther-
mocouple. During deposition the pressure was 170 mtorr, the laser wave-
lenEth was 248 run, the energy density was 1.5 J/cm2/pulse, the pulse rate
was 6 pps, the distance between the target and the sample was 7.5 cm,
and the laser beam was scanned up and down I cm over the target using an
external lens on a translator. The angle between the normal of the tar-
get and the laser beam _ was either 15", 20 ° , or 45".
After deposition the oxygen pressure was raised to 1 atm and the
temperature was lowered to 450 °C at a rate of 2 °Clmin. The temperature
was held at 450 °C for 2 hr before it was lowered to 250 °C at a rate of
Z °C/min. The heater power was then turned off and the sample was
allowed to cool to 40 °C or less before it was removed from the chamber.
Resistance was measured using a standard t-polnt probe technique and
with a current density between 4 to I0 A/cm 2. The contacts to the sample
were made by wire bonding directly to the samples with i by 2 mil gold
ribbon. The spacing between the voltage leads was approximately 3 m_.
RESULTS
The transition temperatures T c of several samples for different
='s and different deposition temperatures T d are given in Table I. As
can be seen for the samples deposited, when a - 20 °, a change of 5 "C in
T d can result in a change in T c of 3 to i0 K. The best films were for
a = _5 ° and T d - 772 "C. When the films made at _ = 15" and • = 20"
are compared, it can be seen that the lower angle gave a higher Tc for
a lower T d .
We observe that the intercept on the normal resistance axls is cor-
related with T c. The closer the intercept is to 0 the higher Tc is,
This is illustrated in Fig. 2 by samples i and 5. Film I had a T d of
772 "C and a T c of 87.7 K, while sample 5 had a T d of 751 °C and a
T c of 75.8 K.
The difference between high T c HTS films and lower T c HT$ films
can also be seen in the morphology. Figure 3(a) is a scanning tunneling
micrograph (SEM) of a film grown at _ = 20" and Td = 751 °C with
T c = 80.1K. One can see the extreme roughness in the surface caused by
1 p-slze crystals growing on the surface. In contrast, in Fig. 3(b) the
TABLE I. - TRANSITION TEMPERATURE Tc OF YBu2Cu30 x THIN
FILMS ON CUBIC ZIRCONIA FOR VARIOUS DEPOSITION
TEMPERATURES AND ANGLES BETWEEN THE TARGET'S
NORMAL AND TI_E LASER BEAM
Sample
number
Angle between
laser beam and
target's normal,
deg
45
45
20
20
20
15
15
15
Deposition
temperature,
Td,
°C
772
772
764
755
751
719
699
696
Transition
temperature,
Tc ,
K
87.7
87.7
83.1
86.0
75.8
83.5
71.3
7_.0
co
co
g
N
|,0 --
.q --
./ --
.b --
•5 --
t I --
, I ---
0
0
J
0
o/
0
0
[]
0
[]
[3
0
0 []
0 [30
[]
0 751 °C, 200
[] 175 hE, q5°
D 0
0
CI
I.__I _ J I I____I______I J_ I I I
;_5 50 15 IO0 125 150 175 200 225 250 275 500 32S
TEMPFRATllrE,K
FIGURE2. - NORMALIZEDRESISTANCEOF YBa2Cu30x FILRSON'CUBICZIRCONIAI't_DEBY LASERABLATION
DIFFERENTDEPOSITIONTEI"_i"ERATLIREANDDIFFERENTANGLEBETWEENTHELASERBEA/'_ANDTttE TARGETS
NORI_AL.
3
o um
(i) FILM DE,SITED AT 751 °C WITH A TC _ 81 K. (b) FILM _SITED AT 775 °C WITH A Tc AT _._ K.
FIGURE 3. - SC_NING ELEETR_ MICROGR_H _ LA_R-ABLA_D YBa2Cu30x _[N FI_ ON CUBIC ZIRC_IA,
film was grown at = = 45" and Td = 772 "C with T c = 87.7 K. This
film was smooth with a very low density of particles on the surface.
The x-ray diffraction pattern of the film in Fig. 3(a) is shown in
Fig. 4. All the m_jor peaks are either from YBa2Cu30 x or from cubic zir-
conia. The 2-0 angle full width of half maximum of the gBa2Cu30 x (005)
line is 1.3 e. This condition indicates that the film was oriented.
100 --
80 --
GO --
IlO --
(002)
20 --(001)
3___
5
<o!o)
<003)
(005)
( 10q)
(100) (200)
LJ
3O
20
(070)
(200)
(001) (400)
SS 80
FIGURE h. - X-RAY DIFFRACTION OF YBa2Cu30x FILM ON CUBIC 7]RCONIA. FILM DEPOSITED
AT 75! °C WITIIA TC OF 81 K,
CONCLUSIONS
To conclude, high-quality YBa2Cu30 x thin films have been groom on
cubic zirconla ((Zr02)0.92 (Y203)0.08) with a T c as high as 87.1K.
The best films were smooth and had few particles on the surface. The
transition temperature of the film was found to be highly dependent on
both the deposition temperature and the angle between the normal of the
target and the laser beam. To obtain the highest T c and have it be
ORIGINAL. PAGE
E_AOK AND WHITE p;-IK:;T_RAPH
reproducible, the temperature of the substrate must be held within 3 "C.
To grow films with high T c at lower temperatures in a partial oxygen
atmosphere, the angle = must be as small as possible.
REFERENCES
I. D. Dijkkamp, T. Venkatesan, X.D. Wu, S.A. Shaheen, N. Jisrawi,
Y.H. Min-Lee, W.L. McLean, M. Croft, Appl. Phys. Lett. 51:619 (1987).
2. X.D. Wu, D. Dijkkamp, S.B. Ogale, A. Inam, E.W. Chase, P.F. Miceli,
C.C. Chang, J.M. Tarascon, and T. Venkatesan, Appl. Phys. Left.
51:861 (1987).
3. J. Narayan, N. Biunno, R. Singh, O.W. Holland, and O. Auciello, Appl.
Phys. Left. 51:1845 (1987).
&. L. Lynds, B.R. Weinberger, G.G. Peterson, and H.A.' Krasinski, Appl.
Phys. Lett. 52:320 (1988).
5. T. Venkatesan, C.C. Chang, D. Dijkkamp, S.B. Ogale, E.W. Chase,
L.A. Farrow, D.M. Hwang, P.F. Micell, S.A. Schwarz, J.M. Tarascon,
X.D. Wu, and A. Inam, J. Appl. Phys. 63:4591 (1988).
6. A.M. Desantolo, M.L. Mandich, S. Sunshine, B.A. Davldson,
R.M. Fleming, P. Marsh, and T.Y. Kometanl, Appl. Phys. Lett. 52:1995
7. F.A. Mirandi, W.L. Gordon, V.O. Helnen, B.T. Eblhara, and K.B.
Bhasin, Measurements of Complex Permlttlvity of Microwave Substrates
in the 20-300 K Temperature Range from 26.5 to &0.0 GHz, NASA
TM-I02123 (1989).
FIGURE CAPTIONS
Figure I. - Schematic of laser ablation experiment.
Figure 2. - Normalized resistance of YBa2cu30 x films on cubic zirconia
made by laser ablation different deposition temperature and different
angle between the laser beam and the targets normal. +(751 °C and
20°), (775 °C and 45 °)
Figure 3. - Scanning electron mlcrograph of laser ablated YBa2Cu30 x thin
film on cubic zlrconia. (a) Film was deposited at 751 °C and had a T c
of 81K. (b) Film was deposited at 775 °C and had a Tc of 86.4 K.
Figure 4. - X-ray diffraction of YBa2Cu30 x film on cubic zirconia. The
film was deposited at 751 "C with a T c of 81K.
5
Report Documentation PageNationa] Aeronautics and
Space Administration
1, Report No, 2. Government Accession No. 3. Recipient's Catalog No.
NASA TM- 102350
4. 5. Report DateTitle and Subtitle
Study of Deposition of YBa2Cu307__ on Cubic Zirconia
7. Author(s)
Joseph D. Warner, Joseph E. Meola, and Kimberly A. Jenkins
9.
12.
Performing Organization Name and Address
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio 44135-3191
Sponsoring Agency Name and Address
National Aeronautics and Space Administration
Washington, D.C. 20546-0001
6. Performing Organization Code
8. Performing Organization Report No.
E-5059
10. Work Unit No.
307-51-00
1t, Contract or Grant No,
13. Type of Report and Period Covered
Technical Memorandum
14. Sponsoring Agency Code
15. Supplementary Notes
Prepared for the Third Annual Conference on Superconductivity and Applications sponsored by The New York
State Institute on Superconductivity, Buffalo, New York, September 19-21, 1989. Joseph D. Warner and Joseph
E. Meola, NASA Lewis Research Center; Kimberly A. Jenkins, Ohio University, Athens, Ohio 45701 and
Summer Intern at NASA Lewis.
16. Abstract
Fihns of YBa2Cu307_ x have been grown on (100) cubic zirconia with 8 percent yttria by laser ablation from
sintered targets of YBa2Cu307_x. The temperature of the zirconia substrate during growth was varied between
700 and 780 °C. The atmosphere during growth was 170 mtorr of oxygen. The fihns were subsequently slowly
cooled in-situ in 1 atm of oxygen. The best films were c-axis aligned and had a transition temperature of 87.7 K.
The superconducting transition temperature and the x-ray diffraction analysis will be reported as a function of the
substrate temperature and of the angle between the laser beam and the targct's normal.
17, Key Words (Suggested by Author(s))
Oxide Superconductors; Superconductors; YBa2CU307;
YBa2CU3OT_,_; YBa2CU3Ox; In-situ; High temperature
superconductors; Thin fihns; Laser ablation; Cubic
zirconia; Partially stabilized cubic zirconia, ZrO2
19. Security Ctassif. (of this report)
Unclassified
NASA FORM 1626 OCT 86
18. Distribution Statement
Unclassified- Unlimited
Subject Category 76
20. Security Classif, (of this page)
Unclassified
21. No of pages
6
iml
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Study of deposition of YBa2Cu3O7-x on cubic zirconia

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