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Fuentealba P, Olea C, Aguilar-Bolados H, Audebrand N, de Santana RC, Doerenkamp C, Eckert H, Magon CJ, Spodine E. Physical properties of new ordered bimetallic phases M 0.25Cd 0.75PS 3 (M = Zn II, Ni II, Co II, Mn II). Phys Chem Chem Phys 2020; 22:8315-8324. [PMID: 32159561 DOI: 10.1039/d0cp00631a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Four bimetallic phases of the thiophosphate family have been synthesized by the cationic exchange reaction using a freshly prepared K0.5Cd0.75PS3 precursor phase and methanolic solutions of nitrates of the divalent cations ZnII, NiII, CoII, and MnII. All the materials were characterized by FTIR, PXRD, SEM-EDXS and (in the case of the diamagnetic compounds) by solid state NMR. For the K0.5Cd0.75PS3 precursor, the X-ray powder diffraction data suggest a modification of the structure, while solid state NMR results confirm that this phase possesses an ordered arrangement of Cd vacancies. The cationic exchange reaction achieves a complete removal of potassium ions (no potassium detected by SEM-EDXS) and re-occupation of the vacancies by divalent cations. Therefore, the obtained compounds have an average composition of M0.25Cd0.75PS3 (M = ZnII, NiII, CoII, MnII) and possess an ordered distribution of the substituent cations. Even with the paramagnetic substitution level of 25%, antiferromagnetic behaviour is present in the phases with MnII, CoII and NiII, as evidenced by dc susceptibility and in the case of the MnII substituted phase by EPR. The cooperative magnetic interactions confirm the conclusion that the paramagnetic ions adopt an ordered arrangement. The analysis by broad band impedance spectroscopy allows to attribute the conductivity in these materials to charge movements in the layers due to the difference in electronegativity of the metal ions. Zn0.25Cd0.75PS3 is the phase that shows the highest conductivity values. Finally, the band gap energies of the bimetallic phases tend to be lower than those of the single-metal phases, probably due to an overlap of the band structures.
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Affiliation(s)
- P Fuentealba
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile. and Centro para el Desarrollo de Nanociencias y Nanotecnología, CEDENNA, Santiago, Chile
| | - C Olea
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.
| | - H Aguilar-Bolados
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.
| | - N Audebrand
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France
| | - R C de Santana
- Instituto de Física, Universidade Federal de Goiás, Goiânia, Brazil
| | - C Doerenkamp
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - H Eckert
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - C J Magon
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - E Spodine
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile. and Centro para el Desarrollo de Nanociencias y Nanotecnología, CEDENNA, Santiago, Chile
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Fuentealba P, Cortes C, Manzur J, Paredes-García V, Venegas-Yazigi D, Silva IDA, de Santana RC, Magon CJ, Spodine E. Magnetic behaviour of bimetallic layered phases M' 0.2Mn 0.8PS 3·0.25 H 2O (M' = Zn II, Cu II, Ni II, Co II). Dalton Trans 2017; 46:14373-14381. [PMID: 29027554 DOI: 10.1039/c7dt03249h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work the magnetic properties of bimetallic phases M'0.2Mn0.8PS3·0.25H2O (M' = CoII, NiII, CuII or ZnII) have been explored and compared with those of the pristine phase MnPS3. Magnetic susceptibility, high field magnetization and electron paramagnetic resonance (EPR) studies reveal that the transition temperature between the antiferromagnetic and paramagnetic order for the pristine phase is shifted to lower values in the bimetallic phases. From magnetization measurements the critical field of the spin-flop transition is found to be dependent on the nature of the added secondary transition metal ion. EPR spectra of all compounds in the temperature range of 8-300 K present a single resonance line shape. Temperature dependence of the EPR parameters, like line width, g values and double integrated area (IDIN), are obtained from the spectra and present a scenario compatible with the magnetization results. The temperature dependence of the first derivative of the product (IDINT) shows two maxima for all samples, with exception of the CoII phase, indicating two critical temperatures, while these critical temperatures could not be clearly determined by dc susceptibility.
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Affiliation(s)
- P Fuentealba
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chille, Santiago, Chile.
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Fuentealba P, Paredes-Garcia V, Venegas-Yazigi D, Silva IDA, Magon CJ, Costa de Santana R, Audebrand N, Manzur J, Spodine E. Magnetic properties of composites based on the intercalation of ZnII and CuII bimetallic macrocyclic complexes in the MnPS3 phase. RSC Adv 2017. [DOI: 10.1039/c7ra05089e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
EPR and magnetic susceptibility data of composites based on MnPS3 show the influence of the intercalated species on their magnetic properties.
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Affiliation(s)
- P. Fuentealba
- Facultad de Ciencias Químicas y Farmacéuticas
- Universidad de Chile
- Santiago
- Chile
- CEDENNA
| | - V. Paredes-Garcia
- CEDENNA
- Santiago
- Chile
- Departamento de Ciencias Químicas
- Universidad Andrés Bello
| | - D. Venegas-Yazigi
- CEDENNA
- Santiago
- Chile
- Facultad de Química y Biología
- Universidad de Santiago de Chile
| | - I. D. A. Silva
- Instituto de Física de São Carlos
- Universidade de São Paulo
- 13560-970 São Carlos
- Brazil
| | - C. J. Magon
- Instituto de Física de São Carlos
- Universidade de São Paulo
- 13560-970 São Carlos
- Brazil
| | | | - N. Audebrand
- Université de Rennes 1
- Institut des Sciences Chimiques de Rennes-UMR 6226
- Rennes
- France
| | - J. Manzur
- Facultad de Ciencias Físicas y Matemáticas
- Universidad de Chile
- Santiago
- Chile
| | - E. Spodine
- Facultad de Ciencias Químicas y Farmacéuticas
- Universidad de Chile
- Santiago
- Chile
- CEDENNA
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Leones R, Fernandes M, Ferreira RAS, Cesarino I, Lima JF, Carlos LD, Bermudez VDZ, Magon CJ, Donoso JP, Silva MM, Pawlicka A. Luminescent DNA- and agar-based membranes. J Nanosci Nanotechnol 2014; 14:6685-6691. [PMID: 25924317 DOI: 10.1166/jnn.2014.9368] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Luminescent materials containing europium ions are investigated for different optical applications. They can be obtained using bio-macromolecules, which are promising alternatives to synthetic polymers based on the decreasing oil resources. This paper describes studies of the DNA- and Agar-europium triflate luminescent membranes and its potential technological applications are expanded to electroluminescent devices. Polarized optical microscopy demonstrated that the samples are birefringent with submicrometer anisotropy. The X-ray diffraction analysis revealed predominantly amorphous nature of the samples and the atomic force microscopy images showed a roughness of the membranes of 409.0 and 136.1 nm for the samples of DNA10Eu and Agar1.11Eu, respectively. The electron paramagnetic resonance spectra of the DNA(n)Eu membranes with the principal lines at g ≈ 2.0 and g ≈ 4.8 confirmed uniform distribution of rare earth ions in a disordered matrix. Moreover, these strong and narrow resonance lines for the samples of DNA(n)Eu when compared to the Agar(n)Eu suggested a presence of paramagnetic radicals arising from the DNA matrix. The emission spectra suggested that the Eu3+ ions occupy a single local environment in both matrices and the excitation spectra monitored around the Eu emission lines pointed out that the Eu3+ ions in the Agar host were mainly excited via the broad band component rather than by direct intra-4f(6) excitation, whereas the opposite case occurred for the DNA-based sample.
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Batagin-Neto A, Assis AP, Lima JF, Magon CJ, Yan L, Shao M, Hu B, Graeff CFO. Light-Induced Structural Change in Iridium Complexes Studied by Electron Spin Resonance. J Phys Chem A 2014; 118:3717-3725. [DOI: 10.1021/jp503831p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Batagin-Neto
- Campus
Experimental de Itapeva, UNESP - Univ Estadual Paulista, Rua Geraldo
Alckmin 519, Itapeva, São
Paulo 18409-010, Brazil
| | - A. P. Assis
- POSMAT
− Programa de Pós-Graduação em Ciência
e Tecnologia de Materiais, UNESP − Univ Estadual Paulista, Bauru, São Paulo 17033-360, Brazil
| | - J. F. Lima
- Instituto
de Física de São Carlos, Universidade de São Paulo, São
Carlos, São Paulo 05508-070, Brazil
| | - C. J. Magon
- Instituto
de Física de São Carlos, Universidade de São Paulo, São
Carlos, São Paulo 05508-070, Brazil
| | - L. Yan
- The University of Tennessee, Knoxville, Tennessee 37996, United States
| | - M. Shao
- The University of Tennessee, Knoxville, Tennessee 37996, United States
| | - B. Hu
- The University of Tennessee, Knoxville, Tennessee 37996, United States
| | - C. F. O. Graeff
- DF-FC, UNESP, Univ Estadual Paulista, Avenida Eng. Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo, 17033-360, Brazil
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Magon CJ, Lima JF, Donoso JP, Lavayen V, Benavente E, Navas D, Gonzalez G. Deconvolution of the EPR spectra of vanadium oxide nanotubes. J Magn Reson 2012; 222:26-33. [PMID: 22820006 DOI: 10.1016/j.jmr.2012.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 05/30/2012] [Accepted: 06/09/2012] [Indexed: 06/01/2023]
Abstract
In this work we report results of continuous wave (CW) electron paramagnetic resonance (EPR) spectroscopy of vanadium oxide nanotubes. The observed EPR spectra are composed of a weak well-resolved spectrum of isolated V(4+) ions on top of an intense and broad structure-less line shape, attributed to spin-spin exchanged V(4+) clusters. With the purpose to deconvolute the structured weak spectrum from the composed broad line, a new approach based on the Krylov basis diagonalization method (KBDM) is introduced. It is based on the discrimination between broad and sharp components with respect to a selectable threshold and can be executed with few adjustable parameters, without the need of a priori information on the shape and structure of the lines. This makes the method advantageous with respect to other procedures and suitable for fast and routine spectral analysis, which, in conjunction with simulation techniques based on the spin Hamiltonian parameters, can provide a full characterization of the EPR spectrum. Results demonstrate and characterize the coexistence of two V(4+) species in the nanotubes and show good progress toward the goal of obtaining high fidelity deconvoluted spectra from complex signals with overlapping broader line shapes.
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Affiliation(s)
- C J Magon
- Instituto de Física de São Carlos, Universidade de São Paulo, Sao Carlos, SP, Brazil.
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Tambelli CC, Donoso JP, Magon CJ, Bueno LA, Messaddeq Y, Ribeiro SJL, de Oliveira LFC, Kosacki I. Glass structure and ion dynamics of lead–cadmium fluorgermanate glasses. J Chem Phys 2004; 120:9638-47. [PMID: 15267977 DOI: 10.1063/1.1712905] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glass structure and fluorine motion dynamics are investigated in lead-cadmium fluorgermanate glasses by means of differential scanning calorimetry, Raman scattering, x-ray absorption (EXAFS), electrical conductivity (EC), and (19)F nuclear magnetic resonance (NMR) techniques. Glasses with composition 60PbGeO(3)-xPbF(2)-yCdF(2) (in mol %), with x+y=40 and x=10, 20, 30, 40, are studied. Addition of metal fluorides to the base PbGeO(3) glass leads to a decrease of the glass transition temperature (T(g)) and to an enhancement of the ionic conductivity properties. Raman and EXAFS data analysis suggest that metagermanate chains form the basic structural feature of these glasses. The NMR study leads to the conclusion that the F-F distances are similar to those found in pure crystalline phases. Experimental results suggest the existence of a heterogeneous glass structure at the molecular scale, which can be described by fluorine rich regions permeating the metagermanate chains. The temperature dependence of the NMR line shapes and relaxation times exhibits the qualitative and quantitative features associated with the high fluorine mobility in these systems.
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Affiliation(s)
- C C Tambelli
- Institute of Physics, USP, P.O. Box 369, 13560-970 São Carlos, SP, Brazil
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Vugman NV, de Araújo MB, Pinhal NM, Magon CJ, da Costa Filho AJ. Electron spin-relaxation via vibronic level of nickel (I) and nickel (III) cyanide complexes in NaCl single crystals. J Magn Reson 2004; 168:132-136. [PMID: 15082258 DOI: 10.1016/j.jmr.2004.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2003] [Revised: 02/05/2004] [Indexed: 05/24/2023]
Abstract
Electron spin-lattice relaxation rates for the low spin [Ni(CN)(4)](1-) and [Ni(CN)(4)](3-) complexes in NaCl host lattice were measured by the inversion recovery technique in the temperature range 7-50K. The data for both paramagnetic species fit very well to a relaxation process involving localized anharmonic vibration modes, also responsible for the g-tensor temperature dependence.
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Affiliation(s)
- N V Vugman
- Instituto de Física-Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21910-240, Brazil.
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Magon CJ, de Souza RR, Costa-Filho AJ, Vidoto EA, Faria RM, Nascimento OR. Spin dynamics study in doped polyaniline by continuous wave and pulsed electron paramagnetic resonance. J Chem Phys 2000. [DOI: 10.1063/1.480869] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Franco RWA, Tambelli CC, Magon CJ, Donoso JP, Messaddeq Y, Ribeiro SJL, Poulain M. Differential scanning calorimetry, x-ray diffraction and 19F nuclear magnetic resonance investigations of the crystallization of InF3-based glasses. J Chem Phys 1998. [DOI: 10.1063/1.476812] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Engelsberg M, Albino J, Franco A, Magon CJ. Nuclear spin-lattice relaxation in the randomly diluted magnetic system KNixMg1-xF3. Phys Rev B Condens Matter 1987; 35:1609-1615. [PMID: 9941578 DOI: 10.1103/physrevb.35.1609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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