The magnetocaloric effect (MCE) in one-dimensional (1D) magnetic nanostructures is optimized for a specific value of the magnetic field $H^{*}$ when applied perpendicularly to the longitudinal direction of the system. Our results reveal that $H^{*}$ corresponds to the saturation field, slightly above the transition from a magnetically stable dipolar-coupled configuration to an unstable one. This MCE-optimizing field explicitly depends on the characteristic magnetic parameters of the system, namely, saturation magnetization ($M_S$) and anisotropy constant ($K$): $H^{*}$ is directly proportional to $M_S^2$, and the anisotropy contribution is equal to the anisotropy field of the particles $H_A=2K/M_S$. Accordingly, the MCE in 1D nanomagnets can be directly tuned by a proper choice of the characteristic $M_S$ and $K$ values of the materials.

• Received 1 March 2012

DOI:https://doi.org/10.1103/PhysRevB.86.104431