%0 Journal Article %T Interpretation of the angular dependence of the de Haas-van Alphen effect in MgB_2 %A A. Carrington %A J. D. Fletcher %A H. Harima %J Physics %D 2004 %I arXiv %R 10.1103/PhysRevB.71.174505 %X We present detailed results for the amplitude and field dependence of the de Haas-van Alphen (dHvA) signal arising from the electron-like $\pi$ sheet of Fermi surface in MgB_2. Our data and analysis show that the dip in dHvA amplitude when the field is close to the basal plane is caused by a beat between two very similar dHvA frequencies and not a spin-zero effect as previously assumed. Our results imply that the Stoner enhancement factors in MgB_2 are small on both the Sigma and Pi sheets. %U http://arxiv.org/abs/cond-mat/0412359v1