We investigate cooling mechanisms in magneto-optically and magnetically trapped erbium. We find efficient sub-Doppler cooling in our trap, which can persist even in large magnetic fields due to the near degeneracy of two Landé $g$ factors. Furthermore, a continuously loaded magnetic trap is demonstrated where we observe temperatures below $25\mu \mathrm{K}$. These favorable cooling and trapping properties suggest a number of scientific possibilities for rare-earth-metal atomic physics, including narrow linewidth laser cooling and spectroscopy, unique collision studies, and degenerate bosonic and fermionic gases with long-range magnetic dipole coupling.

• Received 22 June 2007

DOI:https://doi.org/10.1103/PhysRevA.76.053418