Search results for: J.G.S. Duque

Items from 1 to 20 out of 36 results

article

Phase coexistence and magnetic behavior in the low-dimensional hexagonal cobaltites BaxA1-xCoO3-δ (A = Mg or Ca and 0⩽x⩽0.20)

M.P. Oliveira, S.G. Mercena, C.T. Meneses, C.B.R. Jesus, more

Journal of Magnetism and Magnetic Materials > 2018 > 451 > C > 774-779

In this work, we report on X-ray diffraction and magnetization measurements carried out in the low-dimensional hexagonal cobaltites BaxA1-xCoO3-δ (A = Mg or Ca, 0⩽x⩽0.20 and δ = 0 or 0.4). Polycrystalline samples have been synthesized by solid-state reaction. The Rietveld refinements of the X-ray diffraction patterns show clearly a phase coexistence of both BaCoO2.6 and BaCoO3 hexagonal polytype structures...

article

Anisotropic growth of α-Fe2O3 nanostructures

J.R. Jesus, R.J.S. Lima, K.O. Moura, J.G.S. Duque, more

Ceramics International > 2018 > 44 > 4 > 3585-3589

In this work, we report on the anisotropic growth of α-Fe₂O₃ nanoslabs which are produced by co-precipitation method with the addition of sucrose. In our previous work, we have argued that such behavior can be related with the chelating agent. Experiments of X-ray diffraction (XRD), high-resolution transmission electronic microscopy (HRTEM) and magnetic measurements as a function of temperature and...

article

Study of the dynamic of crystallization of an amorphous Fe40Ni40P14B6 ribbon through Johnson-Mehl-Avrami model

E.B. Peixoto, E.C. Mendonça, S.G. Mercena, A.C.B. Jesus, more

Journal of Alloys and Compounds > 2018 > 731 > C > 1275-1279

The study of the crystallization process of an amorphous Fe₄₀Ni₄₀P₁₄B₆ ribbon which is grown by the melt-spinning is reported. Differential scanning calorimetry (DSC), thermogravimetry (TGA), X-ray diffraction and magnetization measurements are used to investigate its dynamic of crystallization. DSC measurements show that a well-pronounced exothermic peak corresponding to first crystallization changes...

article

Analysis of zero field and field cooled magnetization curves of CoFe2O4 nanoparticles with a T-dependence on the saturation magnetization

E.B. Peixoto, M.H. Carvalho, C.T. Meneses, V.H.V. Sarmento, more

Journal of Alloys and Compounds > 2017 > 721 > C > 525-530

In this work, CoFe₂O₄ nanoparticles embedded inside an amorphous SiO₂ were produced by the sol-gel method through the hydrolysis and condensation of tetraethyl orthosilicate (TEOS). In order to improve the sample homogeneity, a set of samples was prepared for using citric acid. Morphological and magnetic properties have been obtained via transmission electronic microscopy (TEM) and AC and DC magnetization...

article

Structural and magnetic phase transition observed in the YCrO3+γ compound

F.A. Fabian, K.O. Moura, C.C.S. Barbosa, E.B. Peixoto, more

Journal of Alloys and Compounds > 2017 > 702 > C > 244-248

We report on thermogravimetric, structural and magnetization measurements in the YCrO_3+γ compound obtained by the co-precipitation method. The thermogravimentric analyses show that the weight losses which occur at three distinct steps are associated with water evaporation, formation of zircon-type YCrO₄ compound and finally a phase transition from the tetragonal YCrO₄ to the orthorhombic YCrO₃. The...

article

Doping effect on the structural properties of Cu1−x(Ni, Zn, Al and Fe)xO samples (0<x<0.10): An experimental and computational study

J.B. Amaral, R.M. Araujo, P.P. Pedra, C.T. Meneses, more

Journal of Solid State Chemistry > 2016 > 241 > C > 26-29

In this work, the effect of insertion of transition metal, TM (=Ni, Zn, Al and Fe), ions in Cu_1−xTM_xO samples (0<x<0.10) prepared via co-precipitation method is studied through experimental and computational methods. The analyses of X-ray diffraction (XRD) patterns using Rietveld refinement show that i) at x=0, all samples present a monoclinic crystal system with space group C2/c and ii) for...

article

Physical properties of antiferromagnetic single crystal GdIn3

L.S. Silva, E.B. Peixoto, S.G. Mercena, A.A. Coelho, more

Materials Letters > 2016 > 175 > C > 9-12

A sample of GdIn₃ was obtained via the metallic flux technique and its structural, magnetic, and thermodynamic properties were studied. X-ray diffraction (XRD) measurements realized at room temperature were performed in order to verify whether the desired crystalline phase had been obtained. The experimental results show that single crystals were grown successfully by the employed growth technique...

article

Reversal magnetization dependence with the Cr and Fe oxidation states in YFe1−xCrxO3 (0≤x≤1) perovskites

F.A. Fabian, P.P. Pedra, K.O. Moura, J.G.S. Duque, more

Journal of Magnetism and Magnetic Materials > 2016 > 408 > C > 94-98

In this work, we have carried out a detailed study of the magnetic and structural properties of YFe_1−xCr_xO₃ (0≤x≤1) samples with orthorhombic structure obtained by co-precipitation method. Analysis of X-ray diffraction data using Rietveld refinement show that all samples present an orthorhombic crystal system with space group Pnma. Besides, we have observed a reduction of unit cell volume with increasing...

article

Intrinsic dependence of the magnetic properties of CoFe2O4 nanoparticles prepared via chemical methods with addition of chelating agents

E.C. Mendonça, Mayara A. Tenório, S.G. Mecena, B. Zucolotto, more

Journal of Magnetism and Magnetic Materials > 2015 > 395 > C > 345-349

In this work, the effect of addition of different chelating agents on the magnetic properties of cobalt ferrite nanoparticles produced by the combining of both co-precipitation and hydrothermal methods is reported. The Rietveld analyses of X-ray diffraction patterns reveal that our samples are single phase (space group: Fd-3m) with small average sizes. The weight losses observed in the thermogravimetric...

article

Synthesis and characterization of La(Cr,Fe,Mn)O3 nanoparticles obtained by co-precipitation method

F.A. Fabian, P.P. Pedra, J.L.S. Filho, J.G.S. Duque, more

Journal of Magnetism and Magnetic Materials > 2015 > 379 > C > 80-83

Magnetic and structural properties have been investigated in La(Cr,Fe,Mn)O₃ nanoparticles obtained by co-precipitation method. The X-ray diffraction measurements allied to Rietveld method confirm the formation of LaCrO₃, LaFeO₃ and LaMnO₃ nanoparticles with crystal structure orthorhombic (Pbnm), orthorhombic (Pnma) and rhombohedral (R-3c), respectively. We also verified an decreasing in the average...

article

Structural, electronic and magnetic properties of the series of double perovskites (Ca,Sr)2−xLaxFeIrO6

L. Bufaiçal, C. Adriano, R. Lora-Serrano, J.G.S. Duque, more

Journal of Solid State Chemistry > 2014 > 212 > Complete > 23-29

Polycrystalline samples of the series of double perovskites Sr2−xLaxFeIrO6 were synthesized. Their structural, electronic and magnetic properties were investigated by X-ray powder diffraction, Mössbauer spectroscopy, magnetic susceptibility, heat capacity and electrical resistivity experiments. The compounds crystallize in a monoclinic structure and were fitted in space group P21/n, with a significant...

article

Weak ferromagnetic component on the bulk ZnFe2O4 compound

C.B.R. Jesus, E.C. Mendonça, L.S. Silva, W.S.D. Folly, more

Journal of Magnetism and Magnetic Materials > 2014 > 350 > Complete > 47-49

Magnetization data on the bulk ZnFe ₂ O ₄ antiferromagnetic compound (T _N ≈10K) obtained via solid state reaction at different synthesis temperatures show one weak ferromagnetic component at room temperature. We have related it with the cationic disorder effect present on spinel structure of our bulk samples which comes from the magnetic interaction between iron ions sit on...

article

Influence of organic precursor on the structural and magnetic properties of Co3O4 nanoparticles

R.J.S. Lima, K.O. Moura, P.P. Pedra, J.G.S. Duque, more

Physica B: Physics of Condensed Matter > 2012 > 407 > 16 > 3196-3198

Antiferromagnetic Co ₃ O ₄ nanoparticles were synthesized by the coprecipitation method. With the addition of the sucrose as chelating agent (sucrose) the size of the particles was reduced from 54nm to 19nm. The Co ₃ O ₄ nanoparticles exhibit a cubic spinel structure identified for X-ray diffraction (XRD) and confirmed by Rietveld refinement. Scanning Electron Microscopy...

article

Field induced phase transitions on NdRhIn5 and Nd2RhIn8 antiferromagnetic compounds

J.G.S. Duque, R. Lora Serrano, D.J. Garcia, L. Bufaical, more

Journal of Magnetism and Magnetic Materials > 2011 > 323 > 7 > 954-956

In this work, we have investigated the low temperature magnetic phase diagram of the tetragonal NdRhIn ₅ and Nd ₂ RhIn ₈ single crystals by means of temperature and field dependent heat capacity and magnetic susceptibility measurements. These compounds order antiferromagnetically with a Néel temperature (T _N ) of 11 and 10.7K for NdRhIn ₅ and Nd ₂ RhIn...

article

Doping effects on the magnetic properties of NdRhIn5 intermetallic antiferromagnet

R. Lora-Serrano, D.J. Garcia, E. Miranda, C. Adriano, more

Physica B: Condensed Matter > 2009 > 404 > 19 > 3059-3062

We report temperature dependent heat capacity and magnetization measurements on single crystals of Nd1-xLaxRhIn5 (x=0.15, 0.4 and 0.5) and NdRhIn5-xSnx (x=0.08, 0.12 and 0.24). NdRhIn₅ is an antiferromagnetic (AFM) compound with TN≈ 11K which crystallizes in the same layered tetragonal structure of the CeMIn₅ family (M=Rh, Co and Ir), where different ground states can be found by tuning the interplay...

article

Electron spin resonance of Gd3+ in the antiferromagnetic heavy fermion CeIn3 and its reference compound LaIn3

E.M. Bittar, J.G.S. Duque, P.A. Venegas, C. Rettori, more

Physica B: Condensed Matter > 2009 > 404 > 19 > 2995-2998

We report temperature dependent electron spin resonance (ESR) experiments of Gd3+ in CeIn3 and in its reference compound LaIn3 taken in crushed single crystals. For LaIn3 a single Dysonian Gd3+ ESR line with a nearly temperature independent g~2.020(5) is observed, and its linewidth follows a Korringa-like behavior as a function of temperature. From the Korringa rate (ΔH/ΔT~16Oe/K) and g-shift (Δg~0...

article

ESR determination of the crystal field parameters of Nd, Dy, Er, and Yb doped skutterudite CeFe4P12

F.A. Garcia, D.J. Garcia, J.G.S. Duque, P.G. Pagliuso, more

Physica B: Condensed Matter > 2009 > 404 > 19 > 3281-3284

Despite extensive research on the skutterudites for the last decade, their electric crystalline field ground state is still a matter of controversy. By using electron spin resonance measurements we show that an appropriate description of the ground state can be given for the Th cubic symmetry of the Ce1-xRxFe4P12 (R=Dy, Er, Yb, x≲0.003) skutterudite compounds. From the analysis of the ESR data the...

article

Field-dependent collective ESR mode in YbRh2Si2

L.M. Holanda, J.G.S. Duque, E.M. Bittar, C. Adriano, more

Physica B: Condensed Matter > 2009 > 404 > 19 > 2964-2968

Electron spin resonance (ESR) experiments in YbRh₂Si₂ Kondo lattice (TK≃25K) at different field/frequencies (4.1≤ν≤34.4GHz) and H⊥c revealed: (i) a strong field dependent Yb3+ spin–lattice relaxation, (ii) a weak field and T-dependent effective g-value, (iii) a suppression of the ESR intensity beyond 15% of Lu-doping, and (iv) a strong sample and Lu-doping (≤15%) dependence of the ESR data. These...

article

Structural and magnetic properties of nanocrystalline particles in an amorphous Fe73.5Nb3CuSi13.5B9 matrix

L.A. Valenzuela, J.G.S. Duque, C.T. Meneses, W.C. Nunes, more

Journal of Non-Crystalline Solids > 2008 > 354 > 42-44 > 4871-4873

We report structural and magnetic properties of fine particles embedded in an amorphous magnetic matrix. As-quenched amorphous Fe _73.5 Nb ₃ CuSi _13.5 B ₉ ribbons (FINEMET) were submitted to the thermal treatments of several times (1⩽t⩽240min) at 570°C using a conventional furnace. The analyses of the X-ray diffraction patterns at room temperature reveal that our samples...

article

Synthesis and characterization of TM-doped CuO (TM=Fe, Ni)

C.T. Meneses, J.G.S. Duque, L.G. Vivas, M. Knobel

Journal of Non-Crystalline Solids > 2008 > 354 > 42-44 > 4830-4832

Polycrystalline Cu ₁₋ _x TM _x O samples (x=0 and 0.06; TM=Ni ²⁺ and Fe ³⁺ ) were grown using a co-precipitation method. The structural and magnetic properties were investigated by means of temperature dependent magnetic susceptibility and room temperature X-ray powder diffraction (XRPD). The XRPD analyses of the samples reveal the formation of single phase with structure...

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Keywords

MAGNETIC PROPERTIES (6)
X-RAY DIFFRACTION (5)
ELECTRON SPIN RESONANCE (ESR) (3)
ESR (3)
NANOCRYSTALS (3)
AMORPHOUS WIRES (2)
ANTIFERROMAGNETICS (2)
ANTIFERROMAGNETISM (2)
CEF EFFECTS (2)
COCONUT WATER (2)
HEAVY FERMIONS (2)
MAGNETOIMPEDANCE (2)
PEROVSKITE (2)
PROTEIC SOL–GEL PROCESS (2)
[PHYSICAL ASTRONOMY CLASSIFICATION SCHEME] 75.47.PQ (2)
[PHYSICAL ASTRONOMY CLASSIFICATION SCHEME] 75.50.KJ (2)
[PHYSICAL ASTRONOMY CLASSIFICATION SCHEME] 75.60.-D (2)
A. DILUTE MAGNETIC SEMICONDUCTORS (DMS) (1)
A. OXIDES (1)
ALLOYS (1)
AMORPHOUS MATERIALS (1)
ANISOTROPIC GROWTH (1)
ANTIFERROMAGNETIC (1)
ASYMMETRIC MAGNETOIMPEDANCE (1)
B. CHEMICAL SYNTHESIS (1)
BAFE12O19 (1)
BIAS FIELD (1)
C. ELECTRON MICROSCOPY (1)
C. X-RAY DIFFRACTION (1)
CAB6 (1)
CARBON NANOTUBE (1)
CEIN3 (1)
CHELATING AGENTS (1)
CHEMICAL SYNTHESIS (1)
CO-PRECIPITATION (1)
CO-PRECIPITATION METHOD (1)
COERCIVITY (1)
COPPER OXIDE (1)
CRYSTAL FIELD (1)
CRYSTAL-FIELD THEORY AND SPIN HAMILTONIANS (1)
CRYSTALLIZATION (1)
D. CRYSTAL STRUCTURE (1)
D. OPTICAL PROPERTIES (1)
DEFECTS (1)
DIFFERENTIAL SCANNING CALORIMETRY (1)
DOUBLE PEROVSKITE (1)
DYSONIAN LINE SHAPE (1)
DYSONIAN RESONANCE (1)
EFFECT OF SIZE (1)
ELECTRON SPIN RESONANCE (1)
ELECTRONIC STRUCTURE (1)
EU2+ (1)
EXCHANGE BIAS (1)
FE2O3 (1)
FERRIMAGNETISM (1)
FIRST ORDER MAGNETIC PHASE TRANSITION (1)
FRUSTRATION (1)
GROUND STATE (1)
HEMATITE (1)
INTERMETALLIC COMPOUNDS (1)
INTERNAL STRESS (1)
JOHNSON-MEHL-AVRAMI MODEL (1)
JOULE HEATING (1)
LAB6 (1)
MAGNETIC ENTROPY (1)
MAGNETIC FRUSTRATION (1)
MAGNETIC MEASUREMENT (1)
MAGNETIC NANOPARTICLES (1)
MAGNETIC PHASE BOUNDARIES (1)
MAGNETIC STRUCTURES (1)
MAGNETIC TRANSITION (1)
MAGNETOELASTIC ANISOTROPY (1)
MAGNETOINDUCTANCE (1)
MAGNETOTRICTIVE EFFECTS (1)
MULTIFERROIC (1)
NANOPARTICLES (1)
NIFE2O4 (1)
OXIDE MATERIAL (1)
PEROVSKITES (1)
PREFERENTIAL GROWTH (1)
SECOND HARMONIC (1)
SINTERING (1)
SKUTTERUDITES (1)
SOLID STATE REACTION (1)
SPIN–SPIN INTERACTION (1)
SRFE12O19 (1)
SUCROSE (1)
SUPERPARAMAGNETISM (1)
SUSCEPTIBILITY (1)
SYNTHESIS (1)
TBMNO3 (1)
TEM (1)
THERMOGRAVIMETRY (1)
VERWEY TRANSITION (1)
X-RAY DIFFRACTION, DOPANTS (1)
XANES (1)
YBRH2SI2 (1)
ZFC/FC (1)
ZIRCON STRUCTURE (1)
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Journal

Journal of Magnetism and Magnetic Materials (11)
Physica B: Physics of Condensed Matter (10)
Physica B: Condensed Matter (4)
Journal of Alloys and Compounds (3)
Journal of Non-Crystalline Solids (2)
Journal of Solid State Chemistry (2)
Ceramics International (1)
Journal of Physics and Chemistry of Solids (1)
Materials Letters (1)
Solid State Communications (1)
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Search results for: J.G.S. Duque

Phase coexistence and magnetic behavior in the low-dimensional hexagonal cobaltites BaxA1-xCoO3-δ (A = Mg or Ca and 0⩽x⩽0.20)

Anisotropic growth of α-Fe2O3 nanostructures

Study of the dynamic of crystallization of an amorphous Fe40Ni40P14B6 ribbon through Johnson-Mehl-Avrami model

Analysis of zero field and field cooled magnetization curves of CoFe2O4 nanoparticles with a T-dependence on the saturation magnetization

Structural and magnetic phase transition observed in the YCrO3+γ compound

Doping effect on the structural properties of Cu1−x(Ni, Zn, Al and Fe)xO samples (0<x<0.10): An experimental and computational study

Physical properties of antiferromagnetic single crystal GdIn3

Reversal magnetization dependence with the Cr and Fe oxidation states in YFe1−xCrxO3 (0≤x≤1) perovskites

Intrinsic dependence of the magnetic properties of CoFe2O4 nanoparticles prepared via chemical methods with addition of chelating agents

Synthesis and characterization of La(Cr,Fe,Mn)O3 nanoparticles obtained by co-precipitation method

Structural, electronic and magnetic properties of the series of double perovskites (Ca,Sr)2−xLaxFeIrO6

Weak ferromagnetic component on the bulk ZnFe2O4 compound

Influence of organic precursor on the structural and magnetic properties of Co3O4 nanoparticles

Field induced phase transitions on NdRhIn5 and Nd2RhIn8 antiferromagnetic compounds

Doping effects on the magnetic properties of NdRhIn5 intermetallic antiferromagnet

Electron spin resonance of Gd3+ in the antiferromagnetic heavy fermion CeIn3 and its reference compound LaIn3

ESR determination of the crystal field parameters of Nd, Dy, Er, and Yb doped skutterudite CeFe4P12

Field-dependent collective ESR mode in YbRh2Si2

Structural and magnetic properties of nanocrystalline particles in an amorphous Fe73.5Nb3CuSi13.5B9 matrix

Synthesis and characterization of TM-doped CuO (TM=Fe, Ni)

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