Magnetic phase diagrams based on static and dynamic magnetic behaviour in Ru-based superconducting ferromagnets

Abstract

In this work, we present magnetic phase diagrams of a RuSr(2)Eu(1.5)Ce(0.5)Cu(2)O(10-δ) (Ru-1222) superconducting ferromagnet derived from its static and dynamic magnetic responses, measured by temperature and field dependences of dc magnetization and nonlinear ac susceptibility in both low and high magnetic fields. Comparison of magnetic phase diagrams of phase pure and impure samples singles out the intrinsic and extrinsic magnetic features, naturally proposing a unified model of Ru-1222 magnetic behaviour. The results considered within the proposed interpretation indicate full agreement between static and dynamic properties which, if measured in combination, effectively complement each other, uncovering existing ambiguities.

Magnetic phase diagram and correlation between metamagnetism and superconductivity in Ru0.9Sr2YCu2.1O7.9

“…We note that García et al 22 also observed change in the behaviour of the superconducting region at H = 1 kOe in their field dependent resistivity and ac susceptibility measurements. In the phase diagram, the decreasing T irr (H) and T N (H) curves in increasing field may indicate a metamagnetic transition separating AFM from FM state, likely stipulated by spin exchange interactions described in our phase mixture model 4 and built upon in the following works [10][11][12] . The types of temperature and field dependent magnetic orderings shown in the phase diagram have been determined from the NPD measurements, which will be discussed in detail in Sections A and B.…”

“…Magnetization measurements can provide rather unambiguous indication of at least two ferromagnetic phase mixture 4 , which creates grounds for a diversity of magnetic transitions and states due to various form of spin and/or charge exchanges as considered in Refs. [10][11][12] . The neutron powder diffraction (NPD) studies reported in Ref.…”