1. 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

2. 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

3. 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

4. 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

5. I + I - V + V- PCCO Patterned Film Ready For Measurements Sample Preperation

6. Patterning Substrate PCCO Photoresist Chrome Gold Indium SolderTo Computer

7. Measurements at the Ithaca College Low Temperature Physics Lab

8. 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

9. 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

10. 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