Magnetic oxide films

Maksimović³

et al. 2009

J Appl Electrochem

The electrodeposition of the Fe-Ni powders from citrate-ammonium chloride containing electrolytes for different Ni/Fe ions concentration ratios at pH 4.0 was investigated by the polarization measurements. The morphology, chemical composition, and phase composition of the obtained powders were investigated using SEM, EDS, and XRD analysis. EDS analysis of as-deposited alloy powders confirmed anomalous co-deposition of Fe and Ni. A common characteristic for all as-deposited powder samples was the presence of cone-shaped cavities and nodules on the big agglomerates of the order of 200-400 lm. After annealing in air at 400, 600, and 700°C for 3 h, all alloy powders oxidized forming NiO, NiFe 2 O 4 , and Fe 2 O 3 phases in different proportions depending on the original powder composition. The NiFe 2 O 4 phase was found to be dominant in the sample with the highest percentage of Fe after annealing at 600°C.

Section: Introductionmentioning

confidence: 99%

An attempt to produce NiFe2O4 powder from electrodeposited Fe–Ni alloy powders by subsequent recrystallization in air

Lačnjevac

Maksimović³

et al. 2009

J Appl Electrochem

Chemical Vapor Deposition

“…Early work ($1960 s) investigated the use of solid metal halide precursors, but the high temperature (>700 8C) required to vaporize these precursors and the formation of corrosive hydrogen halides hampered further development. [10,11] More volatile metal acetylacetonate precursors, (Ni(acac) 2 and Fe(acac) 3 ), have also been utilized in subsequent studies, [13,26] however using traditional vaporization methods (bubbler or crucible), accurate control of vapor concentrations for the two components in order to obtain stoichiometric films is difficult, often resulting in unwanted impurity phases such as Fe 2 O 3 or NiO. [13] Precursor oligomerization (e.g.,…”

Section: Full Papermentioning

confidence: 99%

“…MgAl 2 O 4 (100) and MgO (100) substrates with cubic normal spinel (a ¼ 0.808 nm) and fcc (2a ¼ 0.842 nm) structure, respectively, are used for film growth due to their close lattice match with nickel ferrite (lattice mismatch of 3% and 1%, respectively). [10,21,22] 2. Results and Discussion…”

Section: Full Papermentioning

confidence: 99%

“…[4][5][6] For instance, the magnetoelectric effect in magnetic/ferroelectric heterostructures is promising for tunable microwave devices, such as filters and phase shifters, offering much faster tuning response and lower power consumption. [7] A wide variety of thin film growth techniques have been developed and investigated in the past few decades for nickel ferrite (and with divalent cation substitutions), including chemical vapor transport, [8,9] CVD, [10][11][12][13][14] sputtering, [15] liquid-phase epitaxy, [16] spin-spray plating, [17] and pulsed laser deposition, [18][19][20][21][22] however the achievement of both high quality (structural, morphological, magnetic, and microwave properties) and thick (1-10 mm range) epitaxial films for microwave device applications remains challenging. [23,24] For instance, pulsed laser deposition of spinel ferrites has been investigated extensively due to the relative ease of stoichiometry control.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Growth of Atomically Smooth Epitaxial Nickel Ferrite Films by Direct Liquid Injection CVD

Li¹,

Wang²,

Iliev³

et al. 2011

Magnetoelectric heterostructures are being actively investigated for utilization in next generation microwave devices such as tunable filters and phase shifters. For efficient microwave absorption and magnetoelectric coupling, relatively thick (>1 mm) epitaxial spinel ferrite films with smooth topographies are required for the magnetic/ferroelectric heterostructures. Towards this goal, direct liquid injection (DLI)-CVD has been utilized for epitaxial growth of nickel ferrite (NiFe 2 O 4 ) films on MgAl 2 O 4 (100) and MgO (100) substrates with high deposition rates. Anhydrous Ni(acac) 2 and Fe(acac) 3 (acac ¼ acetylacetonate) are used as precursor sources dissolved in N,N-dimethyl formamide for the DLI vaporizer system. The influence of deposition temperature on the film properties has been investigated using optimized process conditions for flow of the injected precursors and oxygen. Epitaxial nickel ferrite films of stoichiometric composition are obtained in the temperature range 500-800 8C on both substrates with growth rates in the range 0.6-1.1 mm h À1. Because of changes in the surface diffusion behavior, the film morphology is found to be dependent on the deposition temperature with atomically smooth films being obtained for deposition in the temperature range 600-700 8C. Magnetic measurements reveal an increase in the saturation magnetization for the films with increasing growth temperature, which correlates well with the trend for improved epitaxial growth as indicated by X-ray and Raman spectroscopy measurements. Nickel ferrite films deposited on MgAl 2 O 4 (100) at 800 8C exhibit saturation magnetization very close to the bulk value of 300 emu cm À3.

“…At the same time, NiFe 2 O 4 was found to be a highly reproducible humidity [70] and gas [71,72] sensor material. Numerous techniques, such as ferrite plating [73,74], oxidation of metallic films [75], arc plasma method [76], chemical transport [77,78], chemical vapor deposition [79][80][81][82], the dip coating process [83], spray pyrolysis [84,85], and pulsed wire discharge [86], have been used for the preparation of NiFe 2 O 4 films. The main difficulty of these methods is the limit in the choice of substrate material, since it must be kept at a high temperature after deposition.…”

mentioning

confidence: 99%

Morphology, Chemical, and Phase Composition of Electrodeposited Co–Ni, Fe–Ni, and Mo–Ni–O Powders

Lačnjevac

Modern Aspects of Electrochemistry

2012

The alloy powders of the iron-group metals are of great interest for many industrial applications .Ultrafine Co-Ni powders showed significant promise for future development of hard materials [1,2], magnetic materials [3][4][5], commercial batteries [6], catalysts [7][8][9], catalyzing electroplates [10,11], hydrogen absorbing alloy anodes [12], and magnetoresistive sensors [13,14]. The powders for these applications were made by several different techniques such as mechanical alloying-ball milling [15,16], sonochemical synthesis [17][18][19], chemical reduction [13,14,[20][21][22][23], synthesis in microemulsion [24,25]