  Nuclear spin coherence and relaxation dynamics of all constituent isotopes of
an n-doped CdTe/(Cd,Mg)Te quantum well structure are studied employing
optically detected nuclear magnetic resonance. Using time-resolved pump-probe
Faraday ellipticity, we generate and detect the coherent spin dynamics of the
resident electrons. The photogenerated electron spin polarization is
transferred into the nuclear spin system, which becomes polarized and acts back
on the electron spins as the Overhauser field. Under the influence of resonant
radio frequency pulses, we trace the coherent spin dynamics of the nuclear
isotopes $^{111}$Cd, $^{113}$Cd, and $^{125}$Te. We measure nuclear Rabi
oscillations, the inhomogeneous dephasing time $T_2^*$, the spin coherence time
$T_2$, and the longitudinal relaxation time $T_1$. Furthermore, we investigate
the influence of the laser excitation and the corresponding electron spin
polarization on the nuclear spin relaxation time and find a weak extension of
this time induced by interaction with the electron spins.
