Two Ferromagnetic Phases in Spin-Fermion Systems

Abstract

We consider spin-fermion systems which get their magnetic properties from a system of localized magnetic moments being coupled to conducting electrons. The dynamical degrees of freedom are spin-$s$ operators of localized spins and spin-1/2 fermi operators of itinerant electrons. We develop modified spin-wave theory and obtain that system has two ferromagnetic phases. At the characteristic temperature T* the magnetization of itinerant electrons becomes zero, and high temperature ferromagnetic phase (T*<T<T_C) is a phase where only localized electrons give contribution to the magnetization of the system. An anomalous increasing of magnetization below T* is obtained in a good agrement with experimental measurements of the ferromagnetic phase of UGe2.

References in corpus (5)

• Pressure dependence of the magnetization in the ferromagnetic superconductor UGe_2
• Ferromagnetic superconductivity driven by changing Fermi surface topology
• Coupled CDW and SDW Fluctuations as an Origin of Anomalous Properties of Ferromagnetic Superconductor UGe_2
• Magnetic Properties of a Pressure-induced Superconductor UGe${}_2$
• Heat-capacity anomalies at $T_{sc}$ and $T^{\ast }$ in the ferromagnetic superconductor UGe${}_2$

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• Ferrimagnetism of MnV_2O_4 spinel
• Ferromagnetic phases in spin-Fermion systems
• Sequence of superconducting states in field cooled $FeC{r}_2{S}_4$