The excitation of the ${1}^{+}$, ${2}^{\ensuremath{-}}$, 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 the Gogny type, also containing tensor-isospin terms, are used. We analyze the evolution of the magnetic resonances with an increasing number of neutrons, the relevance of collective effects, the need for a correct treatment of the continuum, and the role of the tensor force.