# Magnetic Relaxation in Dysprosium-dysprosium Collisions

 Title: Magnetic Relaxation in Dysprosium-dysprosium Collisions Author: Newman, Bonna K.; Brahms, Nathan; Au, Yat Shan; Johnson, Cort; Connolly, Colin Bryant; Doyle, John M.; Kleppner, Daniel; Greytak, Thomas J. Note: Order does not necessarily reflect citation order of authors. Citation: Newman, Bonna K., Nathan Brahms, Yat Shan Au, Cort Johnson, Colin B. Connolly, John M. Doyle, Daniel Kleppner, and Thomas J. Greytak. 2011. Magnetic relaxation in dysprosium-dysprosium collisions. Physical Review A 83, no. 1: 012713. Full Text & Related Files: PhysRevA.83.012713.pdf (434.7Kb; PDF) Abstract: The collisional magnetic reorientation rate constant $$\vartheta_{\mathbb{R}}$$ is measured for magnetically trapped atomic dysprosium (Dy), an atom with large magnetic dipole moments. Using buffer gas cooling with cold helium, large numbers (>10$$^{11}$$) of Dy are loaded into a magnetic trap and the buffer gas is subsequently removed. The decay of the trapped sample is governed by collisional reorientation of the atomic magnetic moments. We find $$\vartheta_{\mathbb{R}} = 1.9 \pm 0.5 \times 10^{-11} \, \text{cm}^{3} \, \text{s}^{-1}$$ at 390 mK. We also measure the magnetic reorientation rate constant of holmium (Ho), another highly magnetic atom, and find $$\vartheta_{\mathbb{R}} = 5 \pm 2 \times 10^{-12} \, \text{cm}^3\, \text{s}^{-1}$$ at 690 mK. The Zeeman relaxation rates of these atoms are greater than expected for the magnetic dipole-dipole interaction, suggesting that another mechanism, such as an anisotropic electrostatic interaction, is responsible. Comparison with estimated elastic collision rates suggests that Dy is a poor candidate for evaporative cooling in a magnetic trap. Published Version: 10.1103/PhysRevA.83.012713 Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:11130338 Downloads of this work: