Magnetism of Stripe-Ordered La 5/3Sr 1/3NiO 4

{sup 139}La nuclear magnetic resonance studies reveal markedly different magnetic properties of the two sites created by the charged domain wall formation in La{sub 5/3}Sr {sub 1/3}NiO {sub 4} . Nuclear magnetic resonance is slow compared to neutron scattering; we observe a 30thinspthinspK suppression in magnetic ordering temperature indicating glassy behavior. Applied magnetic field reorients the in-plane ordered moments with respect to the lattice, but the relative orientation of the spins among themselves is stiff and broadly distributed. {copyright} {ital 1999} {ital The American Physical Society }