Spin-wave theory for the biaxial (m=2) Lifshitz point problem in three dimensions

It is known that no long-range order can exist on the boundary between the helical phase (wherein the magnetisation varies spatially in one or more of m distinct directions) and the ferromagnetic phase in the biaxial (m=2) Lifshitz point problem in three dimensions when n, the number of components of the order parameter, is greater than unity. The Guassian (quadratic) spin-wave approximation to the n=2 problem predicts that on this phase boundary correlations decay as power laws at large distance. It is shown here that the presence of a marginal quartic spin-wave operator produces logarithmic corrections to the power laws. © 1980 The Institute of Physics.