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The competition between spin glass (SG), antiferromagnetism (AF) and Kondo effect is studied here in a model which consists of two Kondo sublattices with a gaussian random interaction between spins in differents sublattices with an…

Strongly Correlated Electrons · Physics 2009-11-10 S. G. Magalhaes , A. A. Schmidt , F. M. Zimmer , Alba Theumann , B. Coqblin

The competition among spin glass (SG), ferromagnetism and Kondo effect has been analysed in a Kondo lattice model where the inter-site coupling $J_{ij}$ between the localized magnetic moments is given by a generalized Mattis model…

Disordered Systems and Neural Networks · Physics 2009-11-10 S. G. Magalhães , F. M. Zimmer , P. R. Krebs

The competition between spin glass, ferromagnetism and Kondo effect is analysed here in a Kondo lattice model with an inter-site random coupling $J_{ij}$ between the localized magnetic moments given by a generalization of the Mattis model…

Strongly Correlated Electrons · Physics 2009-11-11 S. G. Magalhaes , F. M. Zimmer , P. R. Krebs , B. Coqblin

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 $J_{K}$ and a random Gaussian…

Strongly Correlated Electrons · Physics 2009-11-11 S. G. Magalhaes , F. M. Zimmer , B. Coqblin

It is presented a theory that describes a spin glass phase at finite temperatures in Kondo lattice systems with an additional RKKY interaction represented by long range, random couplings among localized spins like in the Sherrington-…

Statistical Mechanics · Physics 2009-10-31 Alba Theumann , B. Coqblin , S. G. Magalhaes , A. A. Schmidt

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 $J_{K}$ and an interlattice quantum…

Strongly Correlated Electrons · Physics 2015-06-25 S. G. Magalhaes , F. M. Zimmer , B. Coqblin

The Kondo-Spin Glass competition is studied in a theoretical model of a Kondo lattice with an intra-site Kondo type exchange interaction treated within the mean field approximation, an inter-site quantum Ising exchange interaction with…

Strongly Correlated Electrons · Physics 2009-11-10 Alba Theumann , B. Coqblin

We study magnetic ordering of an extended Kondo-lattice model including an additional on-site Coulomb interaction between the itinerant states. The model is solved in the dynamical mean-field theory using Wilson's numerical renormalization…

Strongly Correlated Electrons · Physics 2009-08-20 Robert Peters , Thomas Pruschke

We use the Popov-Fedotov representation of spin operators to construct an effective action for a Kondo lattice model with quenched disorder at finite temperatures. We study the competition between the Kondo effect and frozen spin order in…

Strongly Correlated Electrons · Physics 2009-10-31 M. N. Kiselev , R. Oppermann

Using a non-Abelian density matrix renormalization group method we determine the phase diagram of the Kondo lattice model in one dimension, by directly measuring the magnetization of the ground-state. This allowed us to discover a second…

Strongly Correlated Electrons · Physics 2009-11-07 I. P. McCulloch , A. Juozapavicius , A. Rosengren , M. Gulacsi

We propose the notion of spin-selective Kondo insulator, which provides a fundamental mechanism to describe the ferromagnetic phase of the Kondo lattice model with antiferromagnetic coupling. This unveils a remarkable feature of the…

Strongly Correlated Electrons · Physics 2012-02-24 Robert Peters , Norio Kawakami , Thomas Pruschke

The ground-state phase diagram of an Ising spin-glass model on a random graph with an arbitrary fraction $w$ of ferromagnetic interactions is analysed in the presence of an external field. Using the replica method, and performing an…

Disordered Systems and Neural Networks · Physics 2012-10-12 M. O. Hase , J. R. L. de Almeida , S. R. Salinas

The magnetic phase diagram of the ferromagnetic Kondo lattice model is determined at T=0 in 1D, 2D, and 3D for various magnitudes of the quantum mechanical localized spins ranging from S=1/2 to classical spins. We consider the ferromagnetic…

Strongly Correlated Electrons · Physics 2007-05-23 J. Kienert , W. Nolting

The competition among spin glass (SG), antiferromagnetism (AF) and local pairing superconductivity (PAIR) is studied in a two-sublattice fermionic Ising spin glass model with a local BCS pairing interaction in the presence of an applied…

Disordered Systems and Neural Networks · Physics 2009-11-11 S. G. Magalhaes , F. M. Zimmer , C. J. Kipper , E. J. Callegari

We study numerically the one-dimensional Kondo and Hund lattices consisting of localized spins interacting antiferro or ferromagnetically with the itinerant electrons, respectively. Using the Density Matrix Renormalization Group we find,…

Strongly Correlated Electrons · Physics 2009-11-10 D. J. Garcia , K. Hallberg , B. Alascio , M. Avignon

A spin-1 atomic gas in an optical lattice, in the unit-filling Mott Insulator (MI) phase and in the presence of disordered spin-dependent interaction, is considered. In this regime, at zero temperature, the system is well described by a…

A mean-field multi-spin interaction spin glass model is analyzed in the presence of a ferromagnetic coupling. The static and dynamical phase diagrams contain four phases (paramagnet, spin glass, ordinary ferromagnet and glassy ferromagnet)…

Disordered Systems and Neural Networks · Physics 2009-10-31 J. A. Hertz , David Sherrington , Th. M. Nieuwenhuizen

In the present work we have analyzed a fermionic infinite-ranged Ising spin glass with a local BCS coupling in the presence of transverse field. This model has been obtained by tracing out the conduction electrons degrees of freedom in a…

Superconductivity · Physics 2009-11-10 F. M. Zimmer , S. G. Magalhaes

We present here a theoretical model in order to describe the competition between the Kondo effect and the spin glass behavior. The spin glass part of the starting Hamiltonian contains Ising spins with an intersite exchange interaction given…

Strongly Correlated Electrons · Physics 2015-05-18 S. G. Magalhaes , F. M. Zimmer , B. Coqblin

In the present work it is studied the fermionic van Hemmen model for the spin glass (SG) with a transverse magnetic field $\Gamma$. In this model, the spin operators are written as a bilinear combination of fermionic operators, which allows…

Strongly Correlated Electrons · Physics 2010-07-13 S. G. Magalhaes , F. M. Zimmer , C. V. Morais
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