The primary goal of this research is to familiarize a student with second generation high temperature superconductor tapes and methods for measuring their critical current and critical temperature. These tapes are used above liquid nitrogen temperatures, making cooling cheaper than with low-temperature superconductors. They have applications in areas like MRI, energy storage, and maglev trains. The tapes are fabricated through complex deposition and involve depositing silver and oxygen annealing. Critical current is measured through a four-probe method applying current and measuring voltage, while patterning the tape decreases chances of burning. Critical temperature is determined through magnetic induction measurements using coils, with a sensor monitoring temperature changes.

1. Research Proposal:
The primary goal of this summer research is to help the student for becoming familiar with
the Second Generation of High Temperature Superconductors, 2G HTS, and the method of
measuring the critical current and critical temperature of these advanced superconductor tapes.
HTS tapes are mainly used at temperatures above the boiling point of liquid nitrogen, which
makes the required cooling system cheaper in comparison with the low temperature
superconductors LTS. HTS tapes are being developed for a wide range of magnetic and energy
applications. The superconductors are widely used in producing the stable and high magnetic fields
required for the Magnetic Resonance Imaging, MRI, and Nuclear Magnetic Resonance, NMR.
They are also used in wind turbine, superconductive wire, Superconducting Magnetic Energy
Storage, SMES, particle accelerators, and magnetic levitation trains, Maglev Trains, and so on.
The RE1Ba2Cu3O7-δ (REBCO, (RE:Rare Earth)) superconductor tapes are fabricated with
the complex and advanced reel-to-reel Metal Organic Chemical Vapor Deposition, MOCVD. Once
the samples are taken out of the MOCVD chamber, the silver layer is deposited on the samples by
a DC magnetron sputtering instrument and followed by oxygen annealing of sputtered samples.
The silver layer provides an alternate current path and reduces the chances of sample burn-out at
high currents during transport current measurements.
The transport Ic measurement is conducted by a four-probe method. A DC current is passed
through the sample by a current source and the voltage is measured by a nanovoltmeter .The
voltage criterion used for Ic measurement is 3 μV/cm. There is a high probability of sample to
burn-out during the transport Ic measurements, due to the high current carrying capacity of HTS
tapes. A typical bridge of 2 mm width is patterned at the center of the tape by a chemical etching
so that current does not flow through the entire tape width and decrease the probability of sample
burning.
Superconductor materials show the zero resistance below TC. Tc measurement provides
qualitative information about the oxygen content and the secondary phases present in the
superconductor tapes. Tc measurement will be done using a lock-in amplifier by magnetic
induction. The sample is inserted between excitation and pick-up coils which are made from Cu
wires. A temperature sensor is used to measure the instantaneous sample temperature and is placed
close to the coil and is in contact with the sample.