A photoinduced change (Delta m(l)) in the magnetization in a ferromagn
etic single crystal gamma-Fe2O3 doped with zinc ions was discovered wi
th a SQUID magnetometer. The effect is observed at temperatures T less
than or equal to 60 K. Analysis of the characteristic features of the
temperature dependences of Delta m(l) showed that the detected change
s caused by the redistribution of the populations of the sublevels of
the ground state multiplet of the Fe2+ ions in an optical pumping cycl
e which leads to efficient cooling of the spin subsystem of the photoc
enters. (C) 1995 American Institute of Physics.