Matthew C. Sullivan

kitefleaUrban and Civil

Nov 15, 2013 (3 years and 8 months ago)

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Growing and Patterning Thin Films of
Pr
2

x
Ce
x
CuO
4
-
Y

Justin Sousa

Marco Salvaggio

Matthew C. Sullivan

Department of Physics,

Ithaca College, Ithaca NY


Superconductivity: What is it?

Superconductivity is the ability of certain materials to
conduct electric currents with zero resistance.



Discovered in 1911 by Heike Kamerlingh Onnes, Mercury: Tc = 4.2K




1987: “High Temperature” Superconductivity,
YBCO
: T
c

= 90K



Current High T
c

is 138 K,
Hg
0.8
Tl
0.2
Ba
2
Ca
2
Cu
3
O
8.33

Meissner Effect

Why Thin Films?

Advantages



Easy to grow within range of 1000 Å ≤ T ≤ 5000 Å



Easy to get uniform currents



Much harder to make measurements on crystals

Substrate: 0.5 mm = 500
μ
m

PCCO
≈ 3000 Å

Film Growth

Check out our video at

www.ithaca.edu/physics

Plume

Heater

Substrate

PCCO

Vacuum Chamber

Pulsed Laser Deposition



KrF Laser:
λ
= 248 nm



Chamber filled with N
2
0



Substrate is 5x5 mm of STO


Heater Temp = 850
o

C

Film Characterization



AC Susceptibility



X
-
Ray Diffraction

I +

I
-

V +

V
-

PCCO

Patterned
Film

Ready For
Measurements

Sample Preperation

Patterning

Substrate

PCCO

Photoresist

Chrome

Gold

Indium Solder

To
Computer

Measurements at the Ithaca College
Low Temperature Physics Lab

Characteristics of PCCO



Pr
2
-
x
Ce
x
CuO
4
-
y
,
x

indicates the cerium concentration



Optimal Doping is
x

= 0.15 with T
c

= 20 K



We have studied the range of 0.13


x



0.19

IV Data for Optimally Doped PCCO

Critical Isotherm

T = 21.60 K

V = KI
a

becomes:



log(V) = a log(I)

where a is the slope.


Ohmic behavior implies

a = 1, K = R

or V = IR

Future Work



Continue to look for the critical exponent in films of different dopings



Measure critical current and critical field in PCCO and YBCO

Thanks to




Dr. Matthew C Sullivan



The Ithaca College Dana Internship Committee



The Center for Superconductivity Research at The University of Maryland