  Excitons in diluted magnetic semiconductors represent excellent probes for
studying the magnetic properties of these materials. Various magneto-optical
effects, which depend sensitively on the exchange interaction of the excitons
with the localized spins of the magnetic ions can be used for probing. Here, we
study core/shell CdSe/(Cd,Mn)S colloidal nanoplatelets hosting diluted magnetic
semiconductor layers. The inclusion of the magnetic Mn$^{2+}$ ions is evidenced
by three magneto-optical techniques using high magnetic fields up to 15 T:
polarized photoluminescence, optically detected magnetic resonance, and
spin-flip Raman scattering. In particular, information on the Mn$^{2+}$
concentration in the CdS shell layers can be obtained from the spin-lattice
relaxation dynamics of the Mn$^{2+}$ spin system.
