  The magnetization (both dc and ac) of pyrochlore Eu2Ti2O7 have been
investigated. Ac susceptibility measurements reveal a new unusual spin freezing
below 35K for pure Eu2Ti2O7. Frequency dependence of these ac peak positions
indicate slow spin relaxation near this temperature and it follows the
Arrhenius formula suggesting a thermally activated relaxation process. The
origin of this spin freezing has been attributed essentially to a single ion
process which is associated to Eu3+ spin relaxation. Non-magnetic dilution by
Y3+ ions also confirms the single ion freezing.
