The Hertz-Millis-Moriya (HMM) theory's description of the stability of the quantum-critical point (QCP) for itinerant ferromagnets was studied. It was argued that a universal negative, nonanalytic contribution to the static magnetic susceptibility is generated by a long-range spatial correlations associated with the Landau damping of the order parameter field. It was also argued that the actual transmission is either towards first order or towards incommensurate ordering. The results show that the singular corrections are specific to the spin problem. The charge susceptibility remained analytic at criticality.
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It is our pleasure to thank A. Abanov, I. Aleiner, A. Andreev, B. Altshuler, D. Belitz, P. Coleman, S. Das ?>Sarma, A. Georges, L. Glazman, A. Finkelstein, Y. B. Kim, T. Kirkpatrick, D. Maslov, A. Millis, M. Norman, O. Parcollet, I. Paul, R. Ramazashvili, Q. Si, and Th. Vojta for stimulating discussions. The research has been supported by NSF DMR 9979749 (A. V. C.).