  The excitation of the $1^+$, $2^-$ and $3^+$ modes in $^{16}$O, $^{22}$O,
$^{24}$O, $^{28}$O, $^{40}$Ca, $^{48}$Ca, $^{52}$Ca and $^{60}$Ca nuclei is
studied with self-consistent random phase approximation calculations.
Finite-range interactions of Gogny type, containing also tensor-isospin terms,
are used. We analyze the evolution of the magnetic resonances with the
increasing number of neutrons, the relevance of collective effects, the need of
a correct treatment of the continuum and the role of the tensor force.
