C. Levillain et al., EFFECTS OF THERMAL SHUNT TO SUBSTRATE ON NORMAL ZONE PROPAGATION IN HIGH T(C) SUPERCONDUCTING THIN-FILMS, Cryogenics, 34(1), 1994, pp. 69-75
Normal zone propagation is examined in high T(c) superconducting (HTSC
) thin films grown on Al2O3 substrates. The transient heat equation is
solved by a two-dimensional numerical model. In fact it appears that
conventional analyses are inappropriate for this kind of HTSC system.
The computational results indicate that the substrate, with its high v
alue of thermal conductivity, is an efficient thermal shunt for the no
rmal zone propagation in the thin film. This effect induces a signific
ant increase in the quench velocity. Furthermore, the substrate is a g
ood stabilizer: the minimum quench energy of the system is high for a
current I far from the critical value I(c); in addition, the HTSC film
is cooled efficiently. Thus the HTSC thin films deposited on a Al2O3
substrate are very stable against a pulsed disturbance or an accidenta
l transition (I much less than I(c)).