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 μm PCCO ≈ 3000 Å

Film Growth Check out our video at 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 SolderTo 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 = 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