Non-analytic behavior of 2D itinerant ferromagnets
  We consider an ordered ferromagnet in the vicinity of a T=0 transition into a paramagnet. We show that the free energy and the transverse and longitudinal static susceptibilities contain non-analyticities which destroy a continuous second-order transition. Depending on the parameters, the transition either becomes first-order, or occurs via an intermediate spiral phase. 
Dmitri V. Efremov, Joseph J. Betouras, Andrey V. Chubukov