Mean-field model for magnetic orders in NpTGa5 with T=Co, Ni or Rh

Abstract

Characteristics of magnetic transitions in NpTGa${}_5$ with T=Co, Ni, Rh are explained in a unified way with use of a crystalline electric field (CEF) model of localized 5$f^4$ electrons. The model takes a CEF doublet and a singlet as local states, and includes dipolar and quadrupolar intersite interactions in the mean-field theory. Diverse ordering phenomena are derived depending on the magnitude of interaction parameters, which qualitatively reproduce the experimentally observed magnetic behaviors in NpTGa${}_5$. The quadrupole degrees of freedom are essential to the diverse magnetic orders. It is argued that NpRhGa${}_5$ is close to a multicritical point where quadrupoles and dipoles with different directions are competing to order.

arXiv comment17 pages, 10 figures

References in corpus (5)

• Octupole Moment as a Hidden Order Parameter in Orbitally Degenerate f-Electron Systems
• Non-Collinear Magnetism due to Orbital Degeneracy and Multipolar Interactions
• Dynamical Effective Medium Theory for Quantum Spins and Multipoles
• A Simple Model for Coupled Magnetic and Quadrupolar Instabilities in Uranium Heavy-Fermion Materials
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Cited by in corpus (2)

• Resonant x-ray scattering study of NpRhGa_5 and NpCoGa_5
• Magnetic Excitations in NpCoGa5