Partially ferromagnetic electromagnet for trapping and cooling neutral atoms to quantum degeneracy

Abstract

We have developed a compact partially ferromagnetic electromagnet to produce an Ioffe-Pritchard trap for neutral atoms. Our structure permits strong magnetic confinement with low power consumption. Compared to the previous iron-core electromagnet [B. Desruelle, V. Boyer, P. Bouyer, G. Birkl, M. Lécrivain, F. Alves, C. Westbrook, and A. Aspect, Eur. Phys. J. D 1, 255 (1998)], it allows for easy compensation of remnant fields and very high stability, along with cost-effective realization and compactness. We describe and characterize our apparatus and demonstrate trapping and cooling of 87Rb atoms to quantum degeneracy. Pure Bose-Einstein condensates containing 106 atoms are routinely realized on a half-minute cycle. In addition we test the stability of the magnetic trap by producing atom lasers.