Non-equilibrium behavior of the magnetization in the helimagnetic phases of the rare earth alloys R_{1-x}Y_{x} (R = Gd, Tb, Dy)

We have performed DC and AC magnetization measurements for the rare-earth magnetic alloy systems Gd_{0.62}Y_{0.38}, Tb_{0.86}Y_{0.14}, and Dy_{0.97}Y_{0.03}. These materials commonly exhibit a proper helical magnetic structure, and ferromagnetic structure at lower temperatures.In all of these materials, a difference between zero-field-cooled (ZFC) magnetization and field-cooled (FC) magnetization and a hysteresis loop in the M-H curve have been observed in the helimagnetic phases. The non-equilibrium behavior is possibly caused by a common nature, e. g., chiral domain structures. In addition to the above behavior, strong non-linearity of the magnetization and slow spin dynamics have been observed around the N'eel temperature only in Gd$_{0.62}$Y$_{0.38}$. The spin-glass like behavior observed in Gd_{0.62}Y_{0.38} could be related to a novel glassy state such as a helical-glass state.Comment: 7pages 4 figures, 20th International Conference on Magnetism (ICM2015

Notes on certain class of analytic functions with negative coefficients

The object of the present paper is to show the extreme points of the class A(n,Bk) consisting of analytic functions with negative coefficients and the support points of the subclass A *(n,Bk) of A(n,Bk)