FIZIKA A 15 (2006) 1 , 17-24
SUPERCONDUCTING PROPERTIES OF THERMALLY-RELAXED Zr80Co20 METALLIC GLASS
IVAN KOKANOVIĆa, BORAN LEONTIĆa and JAGODA LUKATELAb
aDepartment of Physics, Faculty of Science, University of Zagreb,
P.O. Box 331,Zagreb, Croatia
bInstitute of Physics, P.O. Box 304, Zagreb, Croatia
Received 21 September 2004; Accepted 16 May 2005
Online 10 November 2006
We have studied the effect of thermal relaxation on the superconducting
properties of Zr80Co20 metallic glass by means of differential scanning
calorimetry and electrical resistivity measurements in the vicinity of
the superconducting transition temperature Tc. Experimental values for
the crystallisation temperature and activation energy of the
crystallisation processes were derived by studying these processes at
different heating rates. The Tc of the Zr80Co20 metallic glass thermally
relaxed with a heating rate of 60 K/min to slightly below its first
crystallisation exotherm is higher than in unrelaxed Zr80Co20 metallic
glass, whereas in all other thermally relaxed samples Tc decreases
with decreasing heating rates and increasing temperature of relaxation.
The homogeneity of the thermally relaxed Zr80Co20 metallic glass is
discussed by using the superconducting transition width as a criterion.
The superconducting transitions of thermally relaxed Zr80Co20 metallic
glass samples are characterised by a sharp fall in electrical resistance.
This suggests that the samples are homogeneous on a spatial scale of less
than the zero-temperature coherence length x0.
PACS numbers: 61.42.+h, 74.70.Mq
Zr80Co20 metallic glass, thermal relaxation,
superconductivity, transition temperature Tc,
homogeneity, crystallisation exotherm, electrical resistance