Itinerant ferromagnetism in actinide 5f electrons system: Phenomenological analysis with spin fluctuation theory

Abstract

We have carried out an analysis of magnetic data in 69 uranium, 7 neptunium and 4 plutonium ferromagnets with the spin fluctuation theory developed by Takahashi (Y. Takahashi, J. Phys. Soc. Jpn. 55, 3553 (1986)). The basic and spin fluctuation parameters of the actinide ferromagnets are determined and the applicability of the spin fluctuation theory to actinide 5f system has been discussed. Itinerant ferromagnets of the 3d transition metals and their intermetallics follow a generalized Rhodes-Wohlfarth relation between p_eff/p_s and T_C/T_0, viz., p_eff/p_s ~ (T_C/T_0)^(-3/2). Here, p_s, p_eff, T_C, and T_0 are the spontaneous and effective magnetic moments, the Curie temperature and the width of spin fluctuation spectrum in energy space, respectively. The same relation is satisfied for T_C/T_0 < 1.0 in the actinide ferromagnets. However, the relation is not satisfied in a few ferromagnets with T_C/T_0 ~1.0 that corresponds to local moment system in the spin fluctuation theory. The deviation from the theoretical relation may be due to several other effects not included in the spin fluctuation theory such as the crystalline electric field effect on the 5f electrons from ligand atoms. The value of the spontaneous magnetic moment p_s increases linearly as a function of T_C/T_0 in the uranium and neptunium ferromagnets below (T_C/T_0)_kink = 0.32 +- 0.02 where a kink structure appears in relation between the two quantities. p_s increases more weakly above (T_C/T_0)_kink. A possible interpretation with the T_C/T_0-dependence of p_s is given.

References in corpus (11)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Superconductivity on the border of weak itinerant ferromagnetism in UCoGe
• Nature of the 5f states in actinide metals
• The underscreened Kondo lattice model applied to heavy fermion uranium compounds
• Unconventional critical scaling of magnetization in uranium ferromagnetic superconductors UGe${}_2$ and URhGe
• Ferromagnetism in UGe2 : A microscopic model
• Ferromagnetic quantum critical point in UCo1-xFexGe
• Ferromagnetic order in U(Rh,Co)Ge
• Quantum critical scaling in the disordered itinerant ferromagnet UCo${}_{1-x}$Fe${}_x$Ge
• Two Ferromagnetic Phases in Spin-Fermion Systems
• Theoretical Study on Coexistence of Ferromagnetism and Superconductivity

Cited by in corpus (6)

• Superconductivity in high-$T_c$ and related strongly correlated systems from variational perspective: Beyond mean field theory
• Manifestation of electron correlation effect in $\mathrm{U}5f$ states of uranium compounds revealed by $\mathrm{U}4d-5f$ resonant photoemission spectroscopy
• Novel critical behavior of magnetization in URhSi:Similarities to uranium ferromagnetic superconductors UGe${}_2$ and URhGe
• Universal collective modes from strong electronic correlations: Modified $1/{\mathcal{N}}_f$ theory with application to high-$T_c$ cuprates
• Consecutive magnetic phase diagram of UCoGe-URhGe-UIrGe system
• Localization of 5f-electrons and pressure effects on magnetism in U intermetallics in the light of spin-fluctuation theory