Magnetic properties of mixed spinel BaTiO3-NiFe2O4 composites

Sarkar, Babusona; Dalal, Biswajit; Ashok, Vishal Dev; Chakrabarti, Kaushik; Mitra, A.; De, S. K.

doi:10.1063/1.4869782

Cited by 59 publications

(21 citation statements)

References 35 publications

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“…These high Curie temperature magnetic insulators can also be used in spintronics [6] and spincaloritronics (spintransfer torque devices) [7] applications due to their natural non-zero magnetic moment along with spin dependent band gaps. Recently, AB 2 [3,[8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…Ferrimagnetic materials, are an important class of magnetic ceramics, have drawn much attention for the past few decades due to their remarkable properties like high saturation magnetization, large permeability at high frequency, low eddy current, and high electrical resistivity to be utilized in solid state electronics and magneto-electronics [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Chemical bonding and magnetic properties of gadolinium (Gd) substituted cobalt ferrite

Puli

Adireddy

Ramana

2015

Journal of Alloys and Compounds

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Polycrystalline gadolinium (Gd) substituted cobalt ferrites (CoFe 2-x Gd x O 4 ; x=0-0.3, referred to CFGO) ceramics have been synthesized by solid state reaction method. Chemical bonding, crystal structure and magnetic properties of CFGO compounds have been evaluated as a function of Gd-content. X-ray diffraction and Raman spectroscopic analyses confirmed the formation of inverse spinel structure. However, a secondary ortho-ferrite phase (GdFeO 3 ) nucleates for higher values of Gd-content. A considerable increase in the saturation magnetization has been observed upon the initial substitution of Gd (x=0.1). The saturation magnetization drastically decreases at higher Gd content (x≥0.3). No contribution from ortho-ferrite GdFeO 3 phase is noted to the magnetic properties. The increase in the magnetic saturation magnetization is attributed to the higher magnetic moment of Gd 3+ (4f 7 ) residing in octahedral sites is higher when compared to that of Fe 3+ (3d 5 ) and as well due to the migration of Co 2+ (3d 7 ) ions from the octahedral to the tetrahedral sites with a magnetic moment aligned anti-parallel to those of rare earth (RE 3+ ) ions in the spinel lattice. Increase in coercivity with increase in Gd 3+ is content is attributed to magnetic anisotropy in the ceramics.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chemical bonding and magnetic properties of gadolinium (Gd) substituted cobalt ferrite

Puli

Adireddy

Ramana

2015

Journal of Alloys and Compounds

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“…This means the lattice parameter of NiFe2O4 can be determined with an accuracy up to 5 digits beyond the decimal point. Whereas in previous studies with X-ray diffraction [7], the accuracy of lattice parameter was only three digits after the decimal point, namely a = 8.345 Å. This is possible because neutrons interact with the nucleus of the atom, while X-ray interacts with the electrons of the atom.…”

Section: Resultsmentioning

confidence: 93%

“…The importance of neutron diffraction techniques is to obtain an understanding of magnetic structure of the NFO/BTO multiferroic composite. X-ray diffraction study has been done before on the sample of (100-x) BaTiO3/xNiFe2O4 which has been prepared via a two steps standard solid-state reaction method [7]. It was observed in this study that the magnetic structure of NFO in 0.6NFO/0.4BTO composite crystallized into a mixed spinel structure with the cation arrangement of [Ni0.88Fe1.12][Ni0.12Fe0.88]2O4.…”

Section: Introductionmentioning

confidence: 90%

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Neutron Diffraction Study of Multiferroic 0.6NiFe2O4/0.4BaTiO3 Composite

Sukirman

Sarwanto

Ahda

et al. 2020

MST

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Neutron diffraction study on the 0.6NiFe2O4/0.4BaTiO3 multiferroic composite has been carried out. The 0.6NiFe2O4/0.4BaTiO3 multiferroic composites have been synthesized by solid reaction method. In this study, 20 g of BaTiO3 (BTO) and 20 g of NiFe2O4 (NFO) compounds were prepared from the powder raw materials of BaO3 and TiO2 for BTO, and NiO and Fe2O3 for NFO. Furthermore, both BTO and NFO were each crushed for 5 hours using High Energy Milling (HEM). Then the BTO and NFO were calcined in the furnace at 950 °C/5 hours and 900 °C/5 hours, respectively. Both NFO and BTO precursors were manually mixed with a weight percent ratio of NFO:BTO was 100:0, 60:40, and 0:100, hereinafter referred to NFO, NFO/BTO, and BTO, respectively. Then the three samples were pressed into pellets. The pellets were then sintered at 1150 °C/5 hours with a heating rate of about 44.8 °C/min. Once cooled to room temperature within the furnace it was obtained NFO, BTO, and NFO/BTO multiferroic composite. The magnetic properties of the material were observed with the aid of the Vibrating Sample Magnetometer (VSM) instrument. The nuclear structure of BTO, and the magnetic structure of NFO, and NFO/BTO multiferroic composite were determined by neutron diffraction technique using the high resolution powder neutron diffractometer. The cations arrangement of NFO was obtained by whole pattern fitting with the Rietveld method based on neutron diffraction data using FullProf software. The cations arrangement was obtained by refining the occupancy of individual cation at tetrahedral and octahedral sites. The results of the analysis show that both NFO and 0.6NFO/0.4BTO samples have a mixed spinel structure, it means that there are cations of Ni 2+ and Fe 3+ on A-site and B-site. In NFO sample, the cations distribution among the A-site and B-site of NiFe2O4 is [Ni0.002Fe0.852][Ni0.006Fe0.862]2O4. The cations distribution among the A-site and B-site of NiFe2O4 in 0.6NFO/0.4BTO samples is [Ni0.0250Fe0.8975] [Ni0.012Fe0.950]2O4. So, the effect of adding BTO as a composite is to increase Ni 2+ occupancy by 12.5 times on A-site and 2 times on B-site. The magnetic moment of multiferroic 0.6NFO/0.4BTO composite is 2.4(5) µB same as one of NFO. The BTO content in the composite has caused tensile strains induced into the NFO lattice, and at the same time, tensile strains of NFO caused the compressive strain on the c lattice of BTO even though the unit cell volume of BTO is also increasing from 64.100(5) to 64.374(6) Å 3 .

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Magnetic Field Manipulation of Tetrahedral Units in Spinel Oxides for Boosting Water Oxidation

Xiao

Zhang

et al. 2022

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the sluggish kinetics of oxygen evolution reaction (OER) for water splitting still hinders the wide application of this technology. Ru-and Ir-based oxides are highly active catalysts for OER, nevertheless, the scarcity and cost of Ru and Ir largely constrains the broad deployment of hydrogen production utilities. [4][5][6] To this end, transition metal oxide (TMO) electrocatalysts have been extensively investigated due to their earth-abundant and outstanding OER performance. [7][8][9][10] It is remarkable that spinel oxides present stunning catalytic performance for OER in alkaline electrolytes, benefitting from the coexistence of tetrahedral (T d ) and octahedral (O h ) transition-metal cation sites in TMOs, whereas such a complex structure with multiple sites also brings a great challenge on precise identification toward active sites for OER. [11][12][13][14] The tailoring of catalytic active sites for spinel oxides is of importance on the design of highly efficient electrocatalysts for OER, but the active sites of spinel oxides for OER are still elusive. [11,[15][16][17][18] For example, it is reported that the high OER activity of ZnCo 2 O 4 relies on the amounts of Co 3+ on the O h sites. [19] However, on the contrary, it also has been found that the Zn 2+ at T d sites is contributed Magnetic field enhanced electrocatalysis has recently emerged as a promising strategy for the development of a viable and sustainable hydrogen economy via water oxidation. Generally, the effects of magnetic field enhanced electrocatalysis are complex including magnetothermal, magnetohydrodynamic and spin selectivity effects. However, the exploration of magnetic field effect on the structure regulation of electrocatalyst is still unclear whereas is also essential for underpinning the mechanism of magnetic enhancement on the electrocatalytic oxygen evolution reaction (OER) process. Here, it is identified that in a mixed NiFe 2 O 4 (NFO), a large magnetic field can force the Ni 2+ cations to migrate from the octahedral (O h ) sites to tetrahedral (T d ) sites. As a result, the magnetized NFO electrocatalyst (NFO-M) shows a two-fold higher current density than that of the pristine NFO in alkaline electrolytes. The OER enhancement of NFO is also observed at 1 T (NFO@1T) under an operando magnetic field. Our first-principles calculations further confirm the mechanism of magnetic field driven structure regulation and resultant OER enhancement. These findings provide a strategy of manipulating tetrahedral units of spinel oxides by a magnetic field on boosting OER performance.

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Magnetic properties of mixed spinel BaTiO3-NiFe2O4 composites

Cited by 59 publications

References 35 publications

Chemical bonding and magnetic properties of gadolinium (Gd) substituted cobalt ferrite

Chemical bonding and magnetic properties of gadolinium (Gd) substituted cobalt ferrite

Neutron Diffraction Study of Multiferroic 0.6NiFe2O4/0.4BaTiO3 Composite

Magnetic Field Manipulation of Tetrahedral Units in Spinel Oxides for Boosting Water Oxidation

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