Magnetic properties of KClO3-doped Y(1-0.2x)Ba(2-0.2x)KxCu3Oy, (x=0-0.40) HTSC

The influence of KClO3 addition on the magnetic properties and microstructu ral parameters (grain size, grain boundaries) of high-temperature supercond uctors (HTSC) with nominal composition Y(1-0.2x)Ba(2-0.2x)KxCu3Oy (x = 0-0. 40) were investigated. The ac complex susceptibility chi(ac) = chi' - i chi " was recorded as a function of temperature and concentration of KClO3 at various ac magnetic fields up to 2 mT. The data were analysed using the rel ation h = a(1 - T-m/T-c)(n), where T-m represents the intergranular peak te mperature of the imaginary component chi " The value of n is found to incre ase for doped samples, which suggests enhanced flux pinning due to the KClO 3 addition. The de susceptibility as a function of temperature was measured by means of a SQUID magnetometer in field-cooled cooling (FCC) and field-c ooled warming (FCW) modes in magnetic fields in the range 10 mT less than o r equal to mu(0)H(a) less than or equal to 7 T on KClO3-doped and pure YBCO samples. The Meissner curves reveal that the samples are: single phase in all applied fields, but the low-temperature behaviour of the samples with K ClO3 additions is different from that of pure YBCO.