Effects of Al2O3 Nano-Particles on the Irreversible Properties of MgB2 Superconductor

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Effects of Al2O3 Nano-Particles on the
Irreversible Properties of MgB2 Superconductor
183AUS-NANO-07
Kh. A. Ziq Department of Physics, King Fahd
University of Petroleum and Minerals, Dhahran
Saudi Arabia
M. Shahabuddin I. A. Ansari A. F. Salem K.P
Singh H. Kishan
Contact kaziq_at_kfupm.edu.sa
Magnetic measurements on MgB2 SC doped with
various concentration (0 lt x lt 0.6) of Al2O3
nano-particles (20 nm) have been performed in
T-range 4-40K. A significant increase in Hirr,
Jc, Mr- have been observed with increasing the
concentration of the Al2O3 nano-particle.
Vortex-avalanche has been observed in all doped
samples characterized with high critical current
density. Vortex avalanche effect is reduced with
increasing temperature vanishing near 20K. The
results are discussed in terms of local-vortex
instabilities caused by doping of Al2O3
nano-particles
Magnetic Measurements
MgB2/Al2O3 O lt x lt 6 Particle size 20nm.
Samples
10-5 Torr vacuum annealing
Pressure-Temperature Phase Diagram
Low Temperature
600 C
Mg
Under Vacuum
Nanocrystalline Film/Layer
Adam Bridge
Lorentz force pushes vortices (Flux motion)
Local Dissipation of energy Resistance Increase
of temperature Local Quenching in the SC state !!!
Vortex avalanche
Varying flux
Induced emf