We present an investigation of the magnetic properties of the ludwigit
e Ni2FeO2BO3. This material is an oxyborate that presents in its cryst
alline structure subunits in the form of walls where the transition me
tal ions are located. Our Mossbauer, ac susceptibility, and magnetizat
ion measurements show that Fe and Ni ions form two independent subsyst
ems in this material down to T-N=15 K. We explain this behavior in ter
ms of a hierarchy of interactions. [S0163-1829(98)01325-3].