The properties of the low excitation field magnetic response of the granular
high temperature (HTSC) superconductor LaSrCuO have been analyzed at low
temperatures. The response of the Josephson currents has been extracted from
the data. It is shown that intergrain current response is fully irreversible,
producing shielding response, but do not carry Meissner magnetization. Analysis
of the data shows that the system of Josephson currents freezes into a glassy
state even in the absense of external magnetic field, which is argued to be a
consequence of the d-wave nature of superconductivity in LaSrCuO. The
macroscopic diamagnetic response to very weak variations of the magnetic field
is shown to be strongly irreversible but still qualitatively different from any
previously known kind of the critical-state behaviour in superconductors.
A phenomenological description of these data is given in terms of a newly
proposed ``fractal'' model of irreversibility in superconductors.Comment: LATEX, twocolumns, 22 pages including 20 eps-figure
