  The temperature dependence of the magnetisation of a Cu(Mn) spin glass ($T_g$
$\approx$ 57 K) has been investigated using weak probing magnetic fields ($H$ =
0.5 or 0 Oe) and specific thermal protocols. The behaviour of the zero-field
cooled, thermoremanent and isothermal remanent magnetisation on (re-)cooling
the system from a temperature (40 K) where the system has been aged is
investigated. It is observed that the measured magnetisation is formed by two
parts: (i) a temperature- and observation time-dependent thermally activated
relaxational part governed by the age- and temperature-dependent response
function and the (latest) field change made at a lower temperature, superposed
on (ii) a weakly temperature-dependent frozen-in part. Interestingly we observe
that the spin configuration that is imprinted during an elongated halt in the
cooling, if it is accompanied by a field induced magnetisation, also includes a
unidirectional excess magnetisation that is recovered on returning to the
ageing temperature.
