Magnetic ordering in RNiAl compounds (R = Pr, Nd, Tb, Dp, Ho and Er) c
ain be described by a propagation vector k = (1/2,0,q). In most cases
q = 0.5 but incommensurate propagating is observed in PrNiAl (q=0.41)
and NdNiAl (q=0.46). An additional ferromagnetic component exists in H
oNiAl and DyNiAl.