2005/11/24 by S. G. Magalhães, S. G. Magalhaes, F. M. Zimmer +2
Physics and Astronomy · #Ansatz #Antiferromagnetism #Condensed matter physics #Magnetic field #Magnetization #Néel temperature #Phase (matter) #Phase diagram #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum #Quantum critical point #Quantum mechanics #Quantum phase transition #Rare-earth and actinide compounds #Spin glass #Theoretical and Computational Physics #cond-mat.str-el
paper · pdf · doi:10.1016/j.physb.2006.01.051
4 pages, 1 figure, accepted for publication in Physica B
arxiv created 2005/11/24 · openalex publication_date 2006/02/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
A theory is proposed to describe the competition among antiferromagnetism (AF), spin glass (SG) and Kondo effect. The model describes two Kondo sublattices with an intrasite Kondo interaction strength JK and a random Gaussian interlattice interaction in the presence of a transverse field Γ. The Γ field is introduced as a quantum mechanism to produce spin flipping and the random coupling has average -2J0/N and variance 32 J2/N. The path integral formalism with Grassmann fields is used to study this fermionic problem, in which the disorder is treated within the framework of the replica trick. The free energy and the order parameters are obtained using the static ansatz. In this many parameters problem, we choose J0/J ≈ (JK/J)2 and Γ/J ≈ (JK/J)2 to allow a better comparison with the experimental findings. The obtained phase diagram has not only the same sequence as the experimental one for Ce2Au1-xCoxSi3, but mainly, it also shows a qualitative agreement concerning the behavior of the freezing temperature and the Neel temperature which decreases until a Quantum Critical Point (QCP).