Change of the HTSC harmonic susceptibility properties with electrolytic hydrogen loading using different aqueous solution as LiOH and NaOH

The higher harmonics magnetic susceptibilities (/spl chi/=/spl chi//sub i/´+i/spl chi//sub i/´´) of HTSC hydrogen loaded as function of the temperature at 6 G of ac magnetic field amplitude at 107 Hz of frequency have been measured. The samples have been loaded by electrolysis in an aqueous solution using /spl mu/s current pulses at room temperature. The HTSC electrodes have been polarized by short pulse width (1 /spl mu/s) and high peak current (/spl ges/4 A) with a low duty-cycle (10/sup -3/) and a variable repetition rate (1-5 kHz). The hydrogen influence on HTSC (T/sub c/, ac losses) has been measured and the increasing of the superconducting properties, particularly T/sub c/ and J/sub c/, have been found. These effects appear strongly dependent to the loading process and to the stoichiometric ratio H/YBCO. It has been demonstrated that the electrolyte (Li, Na) does not affect the YBCO superconducting properties.