Magneto-optical properties of heavily Fe-doped GaAs: a density functional approach J. Zarpellon, D. H. Mosca, J. Varalda Physical Chemistry Chemical Physics, 2024 Heavily Fe-doped GaAs, investigated using a DFT approach, reveals a spin polarized electronic band structure correlated with magnetic circular dichroism and complex Kerr and Faraday rotation angles in agreement with some previous experiments.
Ferromagnetism in heavily Fe-doped GaAs: a DFT study J Zarpellon, D H Mosca, J Varalda Physica Scripta, 2024 Computational calculations based on density functional theory were carried out to investigate ferromagnetism in gallium arsenide (GaAs) heavily doped with Fe atoms that can substitutionally occupy gallium (Ga) or arsenic (As) sites in the zinc-blende-like crystal structure. The calculations were performed within the spin polarized density functional theory (DFT) and generalized gradient approximation (GGA) with full potential linearized augmented plane wave (FP-LAPW) method. We investigate and discuss the ab initio calculation results focusing on properties intrinsically important for spintronic applications, such as spin polarization and magnetic anisotropy. The density of states (DOS) was calculated with substitution of Fe atoms in the As and Ga sites, giving the electronic properties, as well as the magnetic ground state. According to DFT calculations, heavily doped GaAs with 25 at. % of Fe becomes a ferromagnetic metal with spin polarization as high as 69% at Fermi level. This is corroborated by experimental results previously published in literature.
Size-induced metal-insulator transition temperature decrease of VO2 nanoparticles obtained by laser irradiation in water Bruno S. Beckerle, Alex B. Cezar, Itamar T. Neckel, Wido H. Schreiner, Arandi G. Bezerra, et al. Journal of Applied Physics, 2023 Vanadium dioxide (VO2) is a highly attractive and multifunctional material for technological applications due to its metal–insulator transition, which is accompanied by several orders of magnitude changes in electrical resistivity and optical transmissivity. In this work, we report on the metal–insulator transition of VO2 nanoparticles which are produced by a simple, efficient, and low-cost two-step preparation method based on infrared laser irradiation of V2O5 powder dispersed in water and subsequent stoichiometric stabilization by vacuum annealing at 773 K. VO2 nanoparticles have an average size of 36 nm with facet-like contours and undergo a structural phase transition from a monoclinic to a tetragonal phase, accompanied by a metal–insulator transition occurring around 323 K, which is about 17 K lower than bulk VO2. No evidence of the formation of intermediary metastable phases is observed. Our findings reveal that the size of VO2 nanoparticles is a key parameter to moving the transition closer to room temperature, which is important for many applications.
Ferromagnetic Semiconductor In 0.75 Fe 0.25 Sb for All-Optical Control of Light Polarization MF Ribeiro, J Zarpellon, DH Mosca, J Varalda ACS Omega 11 (12), 18866-18872 , 2026 2026
Magneto-optical properties of quasi-two-dimensional MnGaGe and MnAlGe ferromagnets RMT Araujo, J Zarpellon, DH Mosca, J Varalda Journal of Alloys and Compounds 1010, 178062 , 2025 2025 Citations: 4
Discrimination of vibrational modes in Ni2MnGa thin films AJ Salvador, IT Neckel, D Galante, J Varalda, DH Mosca Journal of Alloys and Compounds 1007, 176306 , 2024 2024
Ferromagnetism in heavily Fe-doped GaAs: a DFT study J Zarpellon, DH Mosca, J Varalda Physica Scripta 99 (9), 095998 , 2024 2024 Citations: 4
The influence of substrate orientation on the magnetic behavior of nearly-stoichiometric Mn5Ge3 thin films: DFT calculations and experimental analysis RC Oliveira, M Marangolo, DH Mosca, J Varalda Journal of Alloys and Compounds 992, 174531 , 2024 2024 Citations: 1
Theoretical approach to defect-induced magnetism in oxygen-deficient γ-Ga2O3 films A Pichorim, IT Neckel, AJA de Oliveira, CA Dartora, J Varalda, DH Mosca Materials Chemistry and Physics 314, 128877 , 2024 2024 Citations: 3
Magneto-optical properties of heavily Fe-doped GaAs: a density functional approach J Zarpellon, DH Mosca, J Varalda Physical Chemistry Chemical Physics 26 (43), 27510-27518 , 2024 2024 Citations: 1
High-temperature vacancy-induced magnetism in nanostructured materials DH Mosca, J Varalda, CA Dartora Physical Review B 108 (13), 134410 , 2023 2023 Citations: 9
Size-induced metal–insulator transition temperature decrease of VO2 nanoparticles obtained by laser irradiation in water BS Beckerle, AB Cezar, IT Neckel, WH Schreiner, AG Bezerra, IL Graff, ... Journal of Applied Physics 134 (12) , 2023 2023 Citations: 6
Magnetic and electronic properties of rare earth free Fe5Ge3 magnets N Melenek, J Varalda Solid State Communications 364, 115118 , 2023 2023 Citations: 1
Room temperature ferromagnetism in oxygen-deficient gallium oxide films with cubic spinel structure A Pichorim, IT Neckel, AJA De Oliveira, J Varalda, DH Mosca Materials Chemistry and Physics 287, 126320 , 2022 2022 Citations: 7
Magnetic and structural properties of Mn5+ xGe3+ y thin films as a function of substrate orientation RC De Oliveira, D Demaille, N Casaretto, YJ Zheng, M Marangolo, ... Journal of Magnetism and Magnetic Materials 539, 168325 , 2021 2021 Citations: 11
Interplay between magnetic moment and magnetocrystalline anisotropy in tetragonally distorted galfenol films R C de Oliveira, V ZC Paes, D H Mosca, J Varalda Journal of Applied Physics 129 (17) , 2021 2021 Citations: 2
Effect of wavelength and fluence in laser-induced iron nitride nanostructures G Gubert, J Varalda, DH Mosca Journal of Alloys and Compounds 856, 157392 , 2021 2021 Citations: 10
Mn5Ge3 ultra-thin films on GaAs (111) B substrates: Influence of initial growth conditions SJ Gutiérrez-Ojeda, RC de Oliveira, HN Fernández-Escamilla, ... Superlattices and Microstructures 148, 106745 , 2020 2020 Citations: 2
Non-conventional ferromagnetism and high bias magnetoresistance in TiO2-x: A simple phenomenological approach VZC Paes, DH Mosca, AJA De Oliveira, J Varalda Journal of Magnetism and Magnetic Materials 497, 166068 , 2020 2020 Citations: 4
Manganese‑germanium nanostructure formation on the GaAs (111)–(1× 1) A surface: Stability and magnetic properties SJ Gutierrez-Ojeda, J Guerrero-Sanchez, R Ponce-Perez, J Varalda, ... Applied Surface Science 491, 147-153 , 2019 2019 Citations: 15
Initial stages of the epitaxial growth of MnN on the GaAs (001)-(2× 2) surface: first-principle study R Ponce-Pérez, MTR de la Cruz, SJ Gutiérrez-Ojeda, J Guerrero-Sánchez, ... Applied Surface Science 489, 639-647 , 2019 2019 Citations: 16
Strain-induced magnetization changes and magneto-volume effects in ferromagnets with cubic symmetry VZC Paes, J Varalda, DH Mosca Journal of Magnetism and Magnetic Materials 475, 539-543 , 2019 2019 Citations: 9
Oxygen diffusion and vacancy migration thermally-activated govern high-temperature magnetism in ceria J Varalda, CA Dartora, PC De Camargo, AJA De Oliveira, DH Mosca Scientific reports 9 (1), 4708 , 2019 2019 Citations: 31
MOST CITED SCHOLAR PUBLICATIONS
Dilute-defect magnetism: Origin of magnetism in nanocrystalline V Fernandes, RJO Mossanek, P Schio, JJ Klein, AJA De Oliveira, ... Physical Review B—Condensed Matter and Materials Physics 80 (3), 035202 , 2009 2009 Citations: 156
Ferromagnetism induced by oxygen and cerium vacancies above the percolation limit in CeO 2 V Fernandes, P Schio, AJA De Oliveira, WA Ortiz, P Fichtner, L Amaral, ... Journal of Physics: Condensed Matter 22 (21), 216004 , 2010 2010 Citations: 89
Room temperature ferromagnetism in Co-doped films on Si(001) V Fernandes, JJ Klein, N Mattoso, DH Mosca, E Silveira, E Ribeiro, ... Physical Review B—Condensed Matter and Materials Physics 75 (12), 121304 , 2007 2007 Citations: 75
Magnetic response of cobalt nanowires with diameter below 5 nm P Schio, F Vidal, Y Zheng, J Milano, E Fonda, D Demaille, B Vodungbo, ... Physical Review B—Condensed Matter and Materials Physics 82 (9), 094436 , 2010 2010 Citations: 52
Oxygen-vacancy-induced room-temperature magnetization in lamellar V2O5 thin films AB Cezar, IL Graff, J Varalda, WH Schreiner, DH Mosca Journal of Applied Physics 116 (16) , 2014 2014 Citations: 50
Enhancement of critical temperature and phases coexistence mediated by strain in MnAs epilayers grown on N Mattoso, M Eddrief, J Varalda, A Ouerghi, D Demaille, VH Etgens, ... Physical Review B—Condensed Matter and Materials Physics 70 (11), 115324 , 2004 2004 Citations: 50
Tuning Fe3O4 nanoparticle dispersion through pH in PVA/guar gum/electrospun membranes AF Lubambo, L Ono, V Drago, N Mattoso, J Varalda, MR Sierakowski, ... Carbohydrate polymers 134, 775-783 , 2015 2015 Citations: 47
Structural, magnetic and spectroscopic study of a diluted magnetic oxide: Co doped CeO 2−δ B Vodungbo, F Vidal, Y Zheng, M Marangolo, D Demaille, VH Etgens, ... Journal of Physics: Condensed Matter 20 (12), 125222 , 2008 2008 Citations: 42
Valence Evaluation of Cerium in Nanocrystalline CeO 2 Films Electrodeposited on Si Substrates V Fernandes, IL Graff, J Varalda, L Amaral, P Fichtner, D Demaille, ... Journal of The Electrochemical Society 159 (1), K27-K33 , 2011 2011 Citations: 41
Structural and magnetic anisotropies of thin films M Marangolo, F Gustavsson, GM Guichar, M Eddrief, J Varalda, ... Physical Review B—Condensed Matter and Materials Physics 70 (13), 134404 , 2004 2004 Citations: 33
Oxygen diffusion and vacancy migration thermally-activated govern high-temperature magnetism in ceria J Varalda, CA Dartora, PC De Camargo, AJA De Oliveira, DH Mosca Scientific reports 9 (1), 4708 , 2019 2019 Citations: 31
Loss of magnetization induced by doping in CeO2 films V Fernandes, P Schio, AJA De Oliveira, WH Schreiner, J Varalda, ... Journal of Applied Physics 110 (11) , 2011 2011 Citations: 30
Resonant tunnel magnetoresistance in epitaxial metal-semiconductor heterostructures J Varalda, A De Oliveira, DH Mosca, JM George, M Eddrief, M Marangolo, ... Physical Review B—Condensed Matter and Materials Physics 72 (8), 081302 , 2005 2005 Citations: 30
Goethite (α-FeOOH) magnetic transition by ESR, Magnetometry and Mössbauer DF Valezi, MT Piccinato, PWC Sarvezuk, FF Ivashita, A Paesano Jr, ... Materials Chemistry and Physics 173, 179-185 , 2016 2016 Citations: 27
Wettability effect of graphene-based surfaces on silicon carbide and their influence on hydrophobicity of nanocrystalline cerium oxide films JC Souza, IT Neckel, J Varalda, E Ribeiro, WH Schreiner, DH Mosca, ... Journal of colloid and interface science 441, 71-77 , 2015 2015 Citations: 26
Tetragonal zinc-blende MnGa ultra-thin films with high magnetization directly grown on epi-ready GaAs (111) substrates AW Arins, HF Jurca, J Zarpellon, J Varalda, IL Graff, AJA De Oliveira, ... Applied Physics Letters 102 (10) , 2013 2013 Citations: 23
Anisotropy of Magnetization and Nanocrystalline Texture in Electrodeposited CeO 2 Films V Fernandes, P Schio, RJO Mossanek, AJA De Oliveira, WA Ortiz, ... Electrochemical and Solid-State Letters 14 (3), P9-P11 , 2011 2011 Citations: 21
Laser irradiation of iron, cobalt, and nickel targets in liquid nitrogen: A facile approach for nitride nanoparticle fabrication of ferromagnetic transition metals G Gubert, E Ribeiro, J Varalda, AG Bezerra Jr, WH Schreiner, DH Mosca Journal of Alloys and Compounds 725, 519-525 , 2017 2017 Citations: 20
Structure and magnetism of MnGa ultra-thin films on GaAs (111) B AW Arins, HF Jurca, J Zarpellon, J Varalda, IL Graff, WH Schreiner, ... IEEE transactions on magnetics 49 (12), 5595-5598 , 2013 2013 Citations: 19
Tunnel magnetoresistance and Coulomb blockade in a planar assembly of cobalt nanoclusters embedded in TiO2 J Varalda, WA Ortiz, AJA De Oliveira, B Vodungbo, YL Zheng, D Demaille, ... Journal of applied physics 101 (1) , 2007 2007 Citations: 18
