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.