Structural parameters and cation distributions in solid state synthesized Ni-Zn ferrites

Gómez, Carlos Andrés Palacio; Meneses, César Augusto Barrero; Matute, Arnaldo

doi:10.1016/j.mseb.2018.12.003

Cited by 34 publications

(3 citation statements)

References 39 publications

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“…Nepouite is often reported to exhibit Ni–Mg substitution in the tetrahedral sites, constituting the lizardite-nepouite series (e.g. 15 , 16 , 20 ), and Ni–Zn substitution is theoretically possible, as the ionic radii of Ni and Zn are quite close to each other in tetrahedral sites (respectively 0.565 Å and 0.580 Å) 23 and their chemistry is very similar, both being chalcophile elements with a similar atomic mass. Although few minerals exhibit extensive Ni–Zn substitution (e.g.…”

Section: Discussionmentioning

confidence: 99%

Ni-rich mineral nepouite explains the exceptional green color of speleothems

Vlieghe,

Rochez,

Pire-Stevenne

et al. 2023

Sci Rep

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Speleothems are secondary mineral structures typically found in karstic caves and usually composed of calcite or aragonite. Despite being naturally white, some might exhibit unusual colors, such as blue, black, red, yellow or green. The causes of these exceptional colorations are poorly understood, especially for green speleothems, which are barely reported. Here we describe the occurrence of the green Ni-bearing serpentine nepouite in green aragonite and calcite speleothems, in the Aven du Marcou (Hérault, France). Nepouite is mainly found as flat lamellar crystals in the outer rim of green speleothems and crystallized alongside radially grown aragonite crystals. This supports nepouite beginning to crystallize recently, due to a change in the chemical composition of the water. Nepouite also exhibits extensive substitution between Ni, Mg and Zn. The various elements responsible for nepouite precipitation are thought to come from the weathering of pyrite crystals in the overlying rocks, which is consistent with the pH conditions of the cave and the Al-free composition of nepouite. This study explains the crystallization mechanisms and stability conditions of silicate minerals in colored caves.

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Section: Discussionmentioning

confidence: 99%

Ni-rich mineral nepouite explains the exceptional green color of speleothems

Vlieghe,

Rochez,

Pire-Stevenne

et al. 2023

Sci Rep

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“…It is also evident from the lower mode gaining more strength and blue shifting while higher mode is red shifting as seen in the table. Generally, the M s depends upon several factors; superexchange (A-B exchange) interaction, moment of atoms, anisotropy constant of magnetic crystals, size of grains, temperatures and a technique for material synthesis [34,35]. The superexchange interaction between the metal ions at Aand B-sites in the spinel structure plays an important role for magnetic order [1].…”

Section: T(ω)mentioning

confidence: 99%

Effect of Co²⁺ substitution on the structural, terahertz and magnetic characterization of NiZn ferrites

Arya¹,

Gandhi²,

Prabhu³

et al. 2021

J. Phys. D: Appl. Phys.

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We present detailed studies on spinel structured Ni0.5Co x Zn0.5−x Fe2O4 (x = 0.1, 0.2 and 0.3), synthesized by sol–gel combustion method. In addition to the structural properties, we present optical dielectric and magnetic response of this system as a function of x. From x-ray diffraction analysis, a single-phase formation in cubic spinel structure was confirmed with an average crystallite size (D avg) variation of 46–61 nm. X-ray diffractograms were analyzed to evaluate the lattice constant (a), x-ray density (ρ x) and porosity (P) in percentage. Energy dispersive x-ray spectroscopy was used to delimit the compositional mass ratios. Terahertz (THz) time-domain spectroscopy measurements were performed to investigate the refractive index ( n ˆ s ) of the samples at room temperature in a frequency range from 0.2 to 2.5 THz. Real and imaginary components of complex optical dielectric constant ( ε ˆ s ) with the increase of Co2+ content were deduced using THz spectroscopy data. The complex optical dielectric constant for the substitution of Co2+ content at x = 0.1, 0.2 and 0.3, was determined within 5% error ∼9.6 + i0.07, ∼10.9 + i0.2 and ∼11.7 + i0.5, respectively. The magnetic measurements were performed at a temperature range of 300–50 K using a superconducting quantum interference device vibrating sample magnetometer under an applied magnetic field of ±5 tesla. We found the highest saturation magnetization (M s) of about 86.7 emu g−1, 83.5 emu g−1 and 80.4 emu g−1 for the substitution of Co2+ content at x = 0.1, 0.2 and 0.3, respectively at room temperature.

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“…, where 2+ and 3+ are the divalent and trivalent cations, respectively, and the round ( ) and square [ ] brackets signify the locations of tetrahedral and octahedral coordination [8]. The literature indicates that the tetrahedral A-sites are exclusively occupied by Zn 2+ ions, while the octahedral B-sites exhibit a preference for Ni 2+ , Mg 2+ , and Co 2+ ions, with varying ratios observed for each ion type [9,10].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and investigation of structural, elastic, and electrical properties of cobalt and magnesium substituted Ni–Zn spinel ferrite nanoparticles

Hasan¹,

Azhdar

2023

J. Phys.: Condens. Matter

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The sol-gel auto-combustion approach was used to create Ni0.4M0.2Zn0.4Fe2O4 (M=Ni2+, Mg2+, and Co2+) nanoparticles. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDS), and an inductance-capacitance-resistance (LCR) meter were used to analyse the samples’ structural, elastic, and electrical properties. In all samples, the XRD patterns obtained indicated the formation of a monophasic cubic spinel structure with no identifiable impurity phase, which was supported by EDS investigations. The introduction of substituting ions, specifically Mg2+ and Co2+, into Ni-Zn ferrite nanoparticles results in an increase in the lattice parameter. The lattice parameter for Ni-Zn is 8.377Ao, while for the substituted nanoparticles it is 8.389 and 8.388 Ao for Mg2+ and Co2+ respectively. Additionally, the crystallite size of the substituted nanoparticles increases to 46.57 nm from 40.75 nm for Ni-Zn. However, the X-ray density of the substituted nanoparticles decreases to 5.180 and 5.337 g/cm3 for Mg2+ and Co2+ respectively, from 5.358 g/cm3 for Ni-Zn. The elastic parameters, such as the Young's modulus, Debye temperature, bulk modulus, and rigidity modulus, were calculated. The good elastic characteristics of Ni-Zn ferrite were confirmed and may be explained by the lower lattice parameter values and smaller crystallite sizes. Temperature and frequency effects on dielectric behaviour and AC electrical conductivity (σAC) were investigated. At ambient temperature, the dielectric characteristics, specifically the dielectric constant (ε') and loss tangent (tanδ), were computed over a frequency range of 100 Hz to 2 MHz. The compositions display normal dielectric properties, which are attributed to the interfacial polarisation following the Maxwell-Wagner model. The AC conductivity of nanoparticles was shown to decrease when Mg2+ and Co2+ were substituted into Ni-Zn ferrite. Furthermore, the AC conductivity diminishes with decreasing frequency, which is a sign of ionic conductivity. There was a direct relationship between the temperature and the values of ε', tanδ, and σAC for different ions.

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Structural parameters and cation distributions in solid state synthesized Ni-Zn ferrites

Cited by 34 publications

References 39 publications

Ni-rich mineral nepouite explains the exceptional green color of speleothems

Ni-rich mineral nepouite explains the exceptional green color of speleothems

Effect of Co²⁺ substitution on the structural, terahertz and magnetic characterization of NiZn ferrites

Synthesis and investigation of structural, elastic, and electrical properties of cobalt and magnesium substituted Ni–Zn spinel ferrite nanoparticles

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Structural parameters and cation distributions in solid state synthesized Ni-Zn ferrites

Cited by 34 publications

References 39 publications

Ni-rich mineral nepouite explains the exceptional green color of speleothems

Ni-rich mineral nepouite explains the exceptional green color of speleothems

Effect of Co2+ substitution on the structural, terahertz and magnetic characterization of NiZn ferrites

Synthesis and investigation of structural, elastic, and electrical properties of cobalt and magnesium substituted Ni–Zn spinel ferrite nanoparticles

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Effect of Co²⁺ substitution on the structural, terahertz and magnetic characterization of NiZn ferrites