Growing and Patterning Thin Films of Pr2 –xCexCuO4-Y

Justin SousaMarco 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: Tc = 90K

• Current High Tc is 138 K, Hg0.8Tl0.2Ba2Ca2Cu3O8.33

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 μm

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 N20• Substrate is 5x5 mm of STO•Heater Temp = 850o C

Film Characterization

• AC Susceptibility

• X-Ray Diffraction

I +

I -V +

V-

PCCOPatterned

Film

Ready For Measurements

Sample Preperation

Patterning

Substrate

PCCO

Photoresist

ChromeGold

Indium Solder To Computer

Measurements at the Ithaca College Low Temperature Physics Lab

Characteristics of PCCO

• Pr2-xCexCuO4-y, x indicates the cerium concentration

• Optimal Doping is x = 0.15 with Tc = 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 = KIa 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