scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Structural and magnetic properties of NiFe2O4 thin films grown on isostructural lattice-matched substrates

TL;DR: In this article, NiFe2O4 thin films are grown epitaxially on two different isostructural substrates, (100)-oriented MgGa2O 4 and ZnGa 2O4, using pulsed laser deposition.
Abstract: Nickel ferrite (NiFe2O4) thin films are grown epitaxially on two different isostructural substrates, (100)-oriented MgGa2O4 and ZnGa2O4, using pulsed laser deposition. These spinel substrates have a lattice mismatch of 0.62% and 0.04%, respectively, with NiFe2O4 crystal. While the films grown on MgGa2O4 substrates exhibit significant strain resulting in a tetragonal distortion of the crystal structure, the films on ZnGa2O4 substrate are essentially strain-free and retain their cubic structure because of the near-perfect lattice match. Magnetometry data suggest that film strain is the principal factor determining the anisotropy of these NiFe2O4 films. This is also confirmed by the effective magnetization values obtained from ferromagnetic resonance (FMR) measurements. While there is only a modest decrease in effective Gilbert damping constant with strain reduction, an enhancement in the spin voltage is observed in the spin Seebeck effect (SSE) measurements for NiFe2O4 films grown on ZnGa2O4 substrate with thickness ≤200 nm.
Citations
More filters
Journal ArticleDOI
TL;DR: In this paper , the light-induced transverse thermoelectric (TTE) effect in c-axis inclined PbSe thin films that were grown epitaxially on c- axis miscut SrTiO 3 single crystal substrates using the pulsed laser deposition technique was reported.
Abstract: PbSe is a simple binary compound that has been studied extensively for use as a promising moderate-temperature thermoelectric material. In this Letter, we report the observation of the light-induced transverse thermoelectric (TTE) effect in c-axis inclined PbSe thin films that were grown epitaxially on c-axis miscut SrTiO 3 single crystal substrates using the pulsed laser deposition technique. Because of the anisotropic Seebeck coefficient of these inclined PbSe thin films, high TTE voltage signals were detected when the film surfaces were irradiated using various different continuous-wave lasers with wavelengths ranging from the ultraviolet (360 nm) to the far infrared (10.6 μm). In addition, the amplitudes of the output voltage signals showed good linear dependence on both the radiation power density and the film inclination angle. The results above demonstrate the potential of PbSe for self-powered ultra-broadband light detection applications.

5 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed to enhance the thermal stability and electrochemical performances of the NCM622 cathode via employing the thermal barrier material as a coating layer, even in other cathodes beyond NCM 622.
Abstract: Poor thermal stability and severe structural degradation of Ni-rich LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode during the (de)lithiation process hinder its further application. As a typical thermal barrier material and ion conductor, La2Zr2O7 (LZO) was herein served as the multifunctional modification layer due to its excellent thermal stability, robust chemical stability, and prominent Li+ conductivity. Through optimizing the contents of LZO, 2 wt.% LZO-coated NCM622 (2LZO-NCM) displayed the much improved cycling stability (66.0% capacity retention at 0.2 °C after 300 cycles at 55 °C) and rate capability (73.0 mAh g−1 at 5 °C) as compared with the pristine NCM622 (59.3%, 22.4 mAh g−1). An aging test, differential scanning calorimetry research, and kinetics analysis were conducted to unveil the improvement mechanism of electrochemical performances for 2LZO-NCM, mainly owing to the relieved structure degradation, boosted thermal stability, and enhanced electrochemical kinetics after LZO modification, synergistically contributing to the improved electrochemical performances. This work provides a universal avenue to enhance the thermal stability and electrochemical performances of the NCM622 cathode via employing the thermal barrier material as a coating layer, even in other cathodes beyond NCM622.

5 citations

Journal ArticleDOI
12 May 2022-Small
TL;DR: Inspired by molecular self-assemblies in nature, a versatile strategy for confined encapsulation of single-atomic metal into high-quality rGO nanosheets by the microwave-assisted emulsion micelle method is reported in this paper .
Abstract: Inspired by molecular self-assemblies in nature, this article reports a versatile strategy for confined encapsulation of single-atomic metal into high-quality rGO nanosheets by the microwave-assisted emulsion micelle method. Multilayer self-assembly of organometallics-surfactants micelles into the interlayer of nanosheets can not only promote microwave exfoliation and reduction of GO but also precisely control loading and distribution of single-metal atoms. With this synthetic strategy, the simultaneous trinity of exfoliation, reduction, and composition are achieved for 1 min. Experimental results and density functional theory calculations demonstrate that graphene-supported FeN4 O2 sites exhibit optimal binding energy toward superior selective adsorption (adsorption amount of 1975.6 mg g-1 with separation efficiency of 97.6%) and electrocatalytic oxidation (TOFs as high as 1.31 min-1 ). This work provides a simple and efficient avenue for the large-scale preparation of single-atomic metal composites in environmental and energy fields.

3 citations

Journal ArticleDOI
TL;DR: In this article , Li+, Al3+, and Ti4+ ions were incorporated into the near surface, and NVP particles were encapsulated by a solid Na+ superionic conductor electrolyte Li1.4Al0.4Ti1.6(PO4)3 (LATP) and carbon (C).
Abstract: Na3V2(PO4)3 (NVP) is a promising cathode for high-energy density sodium-ion batteries, whereas its electrochemical performance is also degraded by its intrinsically inferior electronic conductivity and interfacial side reactions. Herein, Li+, Al3+, and Ti4+ ions were incorporated into the near-surface, and NVP particles were encapsulated by a solid Na+ superionic conductor electrolyte Li1.4Al0.4Ti1.6(PO4)3 (LATP) and carbon (C). Typically, the 0.2 wt. % LATP/C-modified NVP electrode delivers a high initial discharge capacity of 91.22 mA h g−1 and a remarkable rate performance of 56.5 mA h g−1 (20 C). Intensive explorations manifest that the significant improvement in the electrochemical performance of NVP/C could be attributed to the synergistic effects of Li+, Al3+, and Ti4+ doping and the characteristic NVP/LATP/C sandwich coating structure. The modification strategy established in this work synchronously enhanced the electronic conductivity and structural stability of NVP, and this study also provides insight into well-designed electrode microstructures in high-performance batteries.

2 citations

Journal ArticleDOI
TL;DR: In this article , the structural and magnetic properties of the epitaxial CFO films on two isostructural substrates, (001)-oriented MgGa 2 O 4 and ZnGa 2O 4 , using pulsed laser deposition were investigated.
Abstract: Epitaxial thin films of cobalt ferrite (CoFe 2 O 4 ) are grown on two isostructural substrates, (001)-oriented MgGa 2 O 4 and ZnGa 2 O 4 , using pulsed laser deposition. The substrates have a lattice mismatch of 1.26% and 0.70% with bulk CoFe 2 O 4 (CFO) crystal. We have systematically investigated the structural and magnetic properties of the epitaxial CFO films on these substrates. X-ray diffraction and transmission electron microscopy result analysis reveal that the films deposited on spinel ZnGa 2 O 4 are essentially free of defects and are under a small compressive strain, while films on MgGa 2 O 4 show partial strain relaxation along with defect formation. Room temperature magnetization data indicate that CFO grown on ZnGa 2 O 4 substrates have a bulk-like saturation magnetization of 420 emu/cc and a uniaxial substrate-induced anisotropy value of [Formula: see text] [Formula: see text] erg/cm 3 with an anisotropy field as low as 60 kOe.
References
More filters
Journal ArticleDOI
TL;DR: In this paper, a reformulation of the phenomenological theory of the magnetization field was proposed to take large non-eddy-current damping into account in thin Permalloy sheets.
Abstract: In 1955, a phenomenological theory of ferromagnetism was well established and had been corroborated by a considerable amount of experimental data. However, there were problems in the phenomenological theory of the dynamics of the magnetization field. The Landau-Lifshitz equation for damping of the motion of the magnetization field could not account for the large noneddy-current damping in thin Permalloy sheets. The problem undertaken herein is a reformulation of the theory in a way that is more consistent with the theory of damping in other physical systems in order to be able to take large damping into account.

2,181 citations

Journal ArticleDOI
TL;DR: In this article, a pure spin current was injected into a Pt thin film using spin pumping, and it was observed to generate electromotive force transverse to the spin current, consistent with the spin-Hall effect.
Abstract: The inverse process of the spin-Hall effect (ISHE), conversion of a spin current into an electric current, was observed at room temperature. A pure spin current was injected into a Pt thin film using spin pumping, and it was observed to generate electromotive force transverse to the spin current. By changing the spin-current polarization direction, the magnitude of this electromotive force varies critically, consistent with the prediction of ISHE.

1,835 citations

Journal ArticleDOI
TL;DR: In this article, a comprehensive survey of the historical development of the science and technology of ferrite materials as well as applications of the ferrites is presented, with a forecast of the future of ferrites in terms of their chemistry.
Abstract: Ferrites—ceramic ferromagnetic materials—have been considered as highly important electronic materials for more than half a century. During this time, the characteristics of commercial ferrite materials, both soft and hard ferrites, have come to approach theoretical values. The quality of commercial ferrites has been improved through accumulated scientific knowledge and advanced technology. This article provides a comprehensive survey of the historical development of the science and technology of ferrite materials as well as applications of the ferrites. The article also offers a forecast of the future of ferrites in terms of their chemistry.

892 citations

Journal Article
TL;DR: In this paper, the most important results on oxide spintronics were reviewed, emphasizing materials physics as well as spin-dependent transport phenomena, and finally give some perspectives on how the flurry of new magnetic oxides could be useful for next-generation spintronic devices.
Abstract: Concomitant with the development of metal-based spintronics in the late 1980s and 1990s, important advances were made on the growth of high-quality oxide thin films and heterostructures. While this was at first motivated by the discovery of high-temperature superconductivity in perovskite Cu oxides, this technological breakthrough was soon applied to other transition-metal oxides and, notably, mixed-valence manganites. The discovery of colossal magnetoresistance in manganite films triggered intense research activity on these materials, but the first notable impact of magnetic oxides in the field of spintronics was the use of such manganites as electrodes in magnetic tunnel junctions, yielding tunnel magnetoresistance ratios that are one order of magnitude larger than what had been obtained with transition-metal electrodes. Since then, research on oxide spintronics has been intense, with the latest developments focused on diluted magnetic oxides and, more recently, on multiferroics. In this paper, the most important results on oxide spintronics was reviewed, emphasizing materials physics as well as spin-dependent transport phenomena, and finally give some perspectives on how the flurry of new magnetic oxides could be useful for next-generation spintronics devices

301 citations

Journal ArticleDOI
TL;DR: In this article, the most important results on oxide spintronics, emphasizing materials physics as well as spin-dependent transport phenomena, and finally give some perspectives on how the flurry of new magnetic oxides could be useful for next-generation spintronic devices.
Abstract: Concomitant with the development of metal-based spintronics in the late 1980's and 1990's, important advances were made on the growth of high-quality oxide thin films and heterostructures While this was at first motivated by the discovery of high-temperature superconductivity in perovskite Cu oxides, this technological breakthrough was soon applied to other transition metal oxides, and notably mixed-valence manganites The discovery of colossal magnetoresistance in manganite films triggered an intense research activity on these materials, but the first notable impact of magnetic oxides in the field of spintronics was the use of such manganites as electrodes in magnetic tunnel junctions, yielding tunnel magnetoresistance ratios one order of magnitude larger than what had been obtained with transition metal electrodes Since then, the research on oxide spintronics has been intense with the latest developments focused on diluted magnetic oxides and more recently on multiferroics In this paper, we will review the most important results on oxide spintronics, emphasizing materials physics as well as spin-dependent transport phenomena, and finally give some perspectives on how the flurry of new magnetic oxides could be useful for next-generation spintronics devices

238 citations

Trending Questions (1)
What are the differences in the crystal structure and magnetic properties of NiFe and NiFe2O4?

NiFe2O4 films on MgGa2O4 show tetragonal distortion due to strain, while on ZnGa2O4 remain cubic. Strain affects anisotropy and spin voltage, with minor impact on damping constant.