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Related papers: Model for vacancy-induced d$^0$ ferromagnetism in …

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Thermal ammonolysis of quasi-two-dimensional (quasi-2D) CoTa2O6 yields the O2-/N3- and anionic vacancy ordered Co2+Ta5+2O6-xN2x/3$\Box$x/3 (x $\leq$ 0.15) that exhibits a transition from antiferromagnetism to defect engineered above…

It is generally assumed that the application of a charge-current in ferromagnetic metals suppresses their ferromagnetic order through trivial Joule heating. Here, we demonstrate that a charge current can instead enhance magnetic ordering.…

Following the theoretical predictions of ferromagnetism in Mn- and Co-doped ZnO, several workers reported ferromagnetism in thin films as well as in bulk samples of these materials. While some observe room-temperature ferromagnetism, others…

Materials Science · Physics 2007-05-23 C. N. R. Rao , F. L. Deepak

Creating magnetic semiconductors that work at warm circumstance is still a great challenge in the physical sciences. Here, we report the discovery of ferromagnetism in the metal-free perylene diimide semiconductor, whose Curie temperature…

We have prepared magnetic graphite samples bombarded by protons at low temperatures and low fluences to attenuate the large thermal annealing produced during irradiation. An overall optimization of sample handling allowed us to find Curie…

Strongly Correlated Electrons · Physics 2009-11-13 J. Barzola-Quiquia , P. Esquinazi , M. Rothermel , D. Spemann , T. Butz , N. García

The Hubbard model on fcc-type lattices is studied in the dynamical mean-field theory of infinite spatial dimensions. At intermediate interaction strength finite temperature Quantum Monte Carlo calculations yield a second order phase…

Strongly Correlated Electrons · Physics 2009-10-30 Martin Ulmke

Diluted magnetic semiconductors including Mn-doped GaAs are attractive for gate-controlled spintronics but Curie transition at room temperature with long-range ferromagnetic order is still debatable to date. Here, we report the…

We analyze the origin of ferromagnetism as a result of carrier mediation in diluted magnetic oxide semiconductors in the light of the experimental evidence reported in the literature. We propose that a combination of percolation of magnetic…

Materials Science · Physics 2007-09-27 M. J. Calderon , S. Das Sarma

The structural and magnetic effects of non-magnetic vanadium (V) doping in helimagnetic SrFeO$_{3-\delta}$ (SFO) are investigated, focusing on up to 3% substitution at the Fe site. Structural analysis from X-ray diffraction (XRD) and Raman…

We explain a profound complexity of magnetic interactions of some technologically relevant gadolinium intermetallics using an ab-initio electronic structure theory which includes disordered local moments and strong $f$-electron…

Combination of electric fields and Joule self-heating is used to change the oxygen stoichiometry and promote oxygen vacancy drift in a free-standing $\mathrm{(La,Sr)MnO_3}$ thin film microbridge placed in controlled atmosphere. By…

Strongly Correlated Electrons · Physics 2017-02-06 Nicola Manca , Luca Pellegrino , Daniele Marré

We investigate the unusual magnetic properties of nearly-critical, weakly-itinerant ferromagnets with general formula UTX, where T=Rh,Co and X=Ge,Si. As a unique feature about these systems, we show that changes in the V_{df} hybridization…

Strongly Correlated Electrons · Physics 2015-03-19 M. B. Silva Neto , A. H. Castro Neto , J. S. Kim , G. R. Stewart

The dynamics of an F--center created by an oxygen vacancy on the $\mathrm{TiO_{2}(110)}$ rutile surface has been investigated using {\it ab initio} molecular dynamics. These simulations uncover a truly complex, time-dependent behavior of…

Materials Science · Physics 2015-05-19 Piotr M. Kowalski , Matteo Farnesi Camellone , Nisanth N. Nair , Bernd Meyer , Dominik Marx

We investigate effects of doping on formation energy and concentration of oxygen vacancies at a metal oxide surface, using MgO (100) as an example. Our approach employs density-functional theory, where the performance of the…

Materials Science · Physics 2013-05-24 Norina A. Richter , Sabrina Sicolo , Sergey V. Levchenko , Joachim Sauer , Matthias Scheffler

We introduce a path to a possibly new class of magnetic materials whose properties are determined entirely by the presence of a low concentration of specific point defects in their crystal structure. Using model Hamiltonian and ab-initio…

Strongly Correlated Electrons · Physics 2009-11-07 I. S. Elfimov , S. Yunoki , G. A. Sawatzky

Extrinsic levels, formation energies, and relaxation geometries are calculated ab initio for oxygen vacancies in alpha-quartz SiO2. The vacancy is found to be thermodynamically stable in the charge states Q=+3, Q=0, Q=--2, and Q=-3. The…

Materials Science · Physics 2009-10-28 C. M. Carbonaro , V. Fiorentini , S. Massidda

A microscopic theory for rare-earth ferromagnetic hexaborides, such as Eu(1-x)Ca(x)B6, is proposed on the basis of the double-exchange Hamiltonian. In these systems, the reduced carrier concentrations place the Fermi level near the mobility…

Strongly Correlated Electrons · Physics 2009-11-10 Vitor M. Pereira , J. M. B. Lopes dos Santos , Eduardo V. Castro , A. H. Castro Neto

In this paper we present the microscopic origin of the ferromagnetism of Fe0.25TaS2 and its finite-temperature magnetic properties. We first obtain the band structures of Fe0.25TaS2 by the first-principles calculations and find that both…

Materials Science · Physics 2022-03-10 Jin-Hua Wang , Ya-Min Quan , Da-Yong Liu , Liang-Jian Zou

Enhancement of Curie temperature ($T_\mathrm{C}$) of two-dimensional (2D) magnets is immensely desirable for room temperature spintronic applications. Fe$_{5}$GeTe$_{2}$ is an exceptional van der Waals metallic ferromagnet due to its…

Materials Science · Physics 2023-05-09 Sukanya Ghosh , Soheil Ershadrad , Biplab Sanyal

A (II,Mn)VI diluted magnetic semiconductor quantum dot with an integer number of electrons controlled with a gate voltage is considered. We show that a single conduction band electron is able to induce a spontaneous collective magnetization…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 J. Fernández-Rossier , L. Brey