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Vacancy defects in isotropic noncollinear antiferromagnets produce long-range spin textures. By developing a "magnetic elasticity theory", we demonstrate that a vacancy-induced readjustment in the spin configuration decays algebraically…

Strongly Correlated Electrons · Physics 2025-05-23 M. E. Zhitomirsky , Vijay B. Shenoy , Roderich Moessner

We demonstrate how exchange hardening can arise in a chemically-disordered solid solution from a first-principles statistical mechanics approach. A general mixed-basis chemical and magnetic cluster expansion has been developed, and applied…

Materials Science · Physics 2019-10-18 Elizabeth Decolvenaere , Emily Levin , Ram Seshadri , Anton Van der Ven

The investigation of a sizable thermal enhancement of magnetization is put forward for uniaxial ferromagnetic nanoparticles that are placed in a rotating magnetic field. We elucidate the nature of this phenomenon and evaluate the resonant…

Statistical Mechanics · Physics 2016-08-16 S. I. Denisov , T. V. Lyutyy , P. Hänggi

We present systematic theoretical investigations to explore the microscopic mechanisms leading to the formation of antiferromagnetism in Ru2MnZ (Z= Sn,Sb,Ge,Si) full Heusler alloys. Our study is based on first-principles calculations of…

Materials Science · Physics 2015-06-23 Sergii Khmelevskyi , Eszter Simon , Laszlo Szunyogh

Using first-principles plane wave calculations we predict that electronic and magnetic properties of graphene nanoribbons can be affected by defect-induced itinerant states. The band gaps of armchair nanoribbons can be modified by hydrogen…

Mesoscale and Nanoscale Physics · Physics 2008-08-12 M. Topsakal , E. Akturk , H. Sevincli , S. Ciraci

We study the effect of various configurations of vacancies on the magnetic properties of graphene nanoflake (GNF) with screened realistic long-range electron interaction [T. O. Wehling, et. al., Phys. Rev. Lett. 106, 236805 (2011)] within…

Strongly Correlated Electrons · Physics 2023-12-12 V. S. Protsenko , A. A. Katanin

We have analyzed the magnetic interactions of a five orbital model for iron superconductors treated both within Hartree-Fock and Heisenberg approximations. We have found that the exchange constants depend non-trivially on the Fe-As-Fe angle…

Strongly Correlated Electrons · Physics 2012-10-08 M. J. Calderon , G. Leon , B. Valenzuela , E. Bascones

We explore possible ways to manipulate the intrinsic edge magnetism in hexagonal graphene nanoflake with zigzag edges, using density functional theory supplemented with on-site Coulomb interaction. The effect of carrier doping, chemical…

Mesoscale and Nanoscale Physics · Physics 2014-07-08 Mukul Kabir , T. Saha-Dasgupta

In this paper, we study the defects effect on magnetic properties of a nano-square structure. This system is composed with alternate layers consisting of the spins {\sigma}=3/2 and S=1. More precisely, we examine the effect of different…

Statistical Mechanics · Physics 2017-07-07 S. Aouini , S. Ziti , H. Labrim , L. Bahmad

The effect of electronic interactions in graphene with vacancies or resonant scatterers is investigated. We apply dynamical mean-field theory in combination with quantum Monte Carlo simulations, which allow us to treat non-perturbatively…

Mesoscale and Nanoscale Physics · Physics 2011-06-29 P. Haase , S. Fuchs , T. Pruschke , H. Ochoa , F. Guinea

The object of this work is to study the magnetic properties of the Lieb structure based on magnetic particles with core-shell nano-structure. This system is consisting of a ferromagnetic 2D Ising model formed with spins: sigma=1/2, S=1 and…

Strongly Correlated Electrons · Physics 2019-01-08 S. Aouini , S. Ziti , H. Labrim , L. Bahmad

An $S=1/2$ ferromagnetic (F) - antiferromagnetic (AF) random alternating Heisenberg quantum spin chain model is investigated in connection to its realization compound: (CH$_3$)$_2$CHNH$_3$Cu(Cl$_x$Br$_{1-x}$)$_3$. The exchange interaction…

Disordered Systems and Neural Networks · Physics 2009-11-10 Tota Nakamura

Being inspired by a recent study [V. Dimitriadis et al. Phys. Rev. B \textbf{92}, 064420 (2015)], we study the finite temperature magnetic properties of the spherical nanoparticles with core-shell structure including quenched (i) surface…

Statistical Mechanics · Physics 2017-06-28 E. Vatansever , Y. Yuksel

It has been recently pointed out that the presence of a nonmagnetic impurity in a Heisenberg antiferromagnet generates an alternating order of the surrounding spins which is independent of temperature in a wide range. Quantum Monte Carlo…

Strongly Correlated Electrons · Physics 2008-06-11 Ruggero Vaia , Alessandro Cuccoli

We study the possibility of nanoscale phase separation in manganites in the framework of the double exchange model. The homogeneous canted state of this model is proved to be unstable toward the formation of small ferromagnetic droplets…

Strongly Correlated Electrons · Physics 2009-11-10 M. Yu. Kagan , A. V. Klaptsov , I. V. Brodsky , K. I. Kugel , A. O. Sboychakov , A. L. Rakhmanov

We investigate the consequences for geometrically frustrated antiferromagnets of weak disorder in the strength of exchange interactions. Taking as a model the classical Heisenberg antiferromagnet with nearest neighbour exchange on the…

Strongly Correlated Electrons · Physics 2007-05-23 T. E. Saunders , J. T. Chalker

We examine binary mixtures of superparamagnetic colloidal particles confined to a two-dimensional water-air interface both by real-space experiments and Monte-Carlo computer simulations at high coupling strength. In the simulations, the…

Soft Condensed Matter · Physics 2015-05-13 L Assoud , F Ebert , P Keim , R Messina , G Maret , H Löwen

High fraction of the surface atoms considerably enhances the influence of size and shape on the magnetic and electronic properties of nanoparticles. Shape effects in ferromagnetic nanoparticles are well understood and allow to set and…

Mesoscale and Nanoscale Physics · Physics 2013-08-16 H. Gomonay , S. Kondovych , V. Loktev

We study proximity effect in a tunnel junction between a bulk superconductor and a thin disordered ferromagnetic layer on its surface. Cooper pairs penetrating from the superconductor into the ferromagnet tend to destabilize its uniform…

Disordered Systems and Neural Networks · Physics 2025-12-10 A. V. Levin , P. M. Ostrovsky

When two or more metallic nanoparticles are in close proximity, their plasmonic modes may interact through the near field, leading to additional resonances of the coupled system or to shifts of their resonant frequencies. This process is…