La2CuO4 is considered as the parent material of all high temperature superconductors. The magnetic nature of the material is antiferromagnetic and it is an insulator. During this research we produced a superconductor by doping ceramic La2CuO4 with excess oxygen. There are different methods to intercalate excess oxygen into a sample, but in this project we used an electrochemical method. After oxidation, the superconducting properties were measured using a Quantum Design MPMS SQUID magnetometer. The superconducting transition temperature (TC) was observed near 40 K with a superconducting volume fraction of 16%. Further oxidation increased the superconducting volume fraction to 48.3% with the same observed TC. According to previous work, super-oxygenated La2CuO4+y material phase separates into an oxygen rich superconducting phase with a TC near 40 K and an oxygen poor magnetic phase that also orders near 40 K. In order to study the magnetic phase closely, we grew a thin film with thickness near 200nm of La2CuO4 on a LaAl2O3 substrate using a Pulse Laser Deposition (PLD) chamber. We checked the epitaxial growth of the film using an X-ray diffraction technique and verified that the thin film was grown correctly. We found that the electrochemical technique is not suitable to dope excess oxygen into the thin film because it ruins the surface. Therefore, as a part of this project we designed an ozone generation system to attach to the PLD. This will help us to grow thin films in an oxygen rich environment and produce superconducting films with better surface qualities.
Superconducting Phases in Bulk and Thin Film LA2CuO4.
Undergraduate Review, 4, 85-92.
Available at: http://vc.bridgew.edu/undergrad_rev/vol4/iss1/17
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