Field-induced phase transitions in the helical state of dysprosium

Abstract

The field-induced magnetic phase transitions of the helical phase of dysprosium are investigated with a vibrating samples magnetometer by measuring isothermal ma gnetization curves for internal magnetic fields up to H = 3 × 106 A/m applied in the basal plane parallel to one of the 〈1120〉-axes. The characteristic features of the magnetization curves are explained in terms of the different spin structures existing in the temperature range between TC = 85 K and TN = 179 K. The temperature dependence of the critical fields inducing magnetic phase transitions between the ferromagnetic, the helical, and the fan structure are determined. In this way the H–T-phase diagram of the spin structures of dysprosium as well as the temperature dependence of the exchange integral are established.