  Magnetic and electric properties of a single crystal of La0.7Ca0.3CoO3 have
been experimentally studied. The system attains a ferromagnetic spontaneous
moment below 170 K and exhibits a re-entrant spin-glass phase below 100 K. In
the ordered and the re-entrant phases, the low field magnetic properties are
strongly direction dependent, showing considerably higher magnetization values
perpendicular than parallel to the c-axis. Magnetic relaxation experiments show
that both the ferromagnetic and the re-entrant spin-glass phases are
non-equilibrium states, where the system exhibits magnetic aging characteristic
of spin-glasses and disordered and frustrated ferromagnets.
