  First-order field-induced spin reorientation transitions in multisublattice
intermetallic compounds are considered within an anisotropic Heisenberg model.
Unlike previous works, only leading-order anisotropy constants of the
sublattices are included. The exchange interactions both between the rare-earth
(RE) and transition metal (TM) sublattices and within the RE sublattice play an
important role in the model. The latter interaction results in the occurrence
of metastable states. One of the minima corresponds to the non-collinear
magnetic structure where the RE subsystem is divided into two sublattices, and
their moments deviate in opposite directions from the TM moment direction. The
possible FOMP scenarios for R$_2$Fe$_{17}$, HoFe$_{11}$Ti, and TbMn$_6$Sn$_6$
systems are discussed.
