Search query: spintronic cobalt ferite

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abstract: Abstract In this work, TiO2:Co thin films were prepared by the DC Magnetron Co Sputtering system on glass substrates, varying the substrate temperature. The magnetron power for each target (TiO2, Co) work pressure and deposition time in the samples were kept constant. From XRD, XPS and EDXS measurements, it was possible to establish the formation of a TiO2 semiconductor matrix without binary phases of cobalt oxides. AFM and MFM micrographs evidenced the formation of smaller grains without domains in the surface. The magnetic curves show the dependence of the substrate temperature in the magnetic behaviour of thin films. The presences of hysteresis loops at high temperature in the thin films were observed.
author_names: Heiddy P Quiroz

A Dussan
title: Synthesis temperature dependence on magnetic properties of cobalt doped TiO2 thin films for spintronic applications
venue: Applied Surface Science
year: 2019

abstract: Cobalt oxide films are of technological interest as magnetic substrates that may support the direct growth of graphene, for use in various spintronic applications. In this work, we demonstrate the controlled growth of both Co_3O_4(111) and CoO(111) on Ru(0001) substrates. The growth is performed by Co molecular beam epitaxy, at a temperature of 500 K and in an O_2 partial pressure of 10^ 4) Torr for Co_3O_4(111) and 7.5 x 10^ 7) Torr for CoO(111) The films are distinguished by their dissimilar Co 2p x ray photoemission (XPS) spectra, while XPS derived O/Co stoichiometric ratios are 1.33 for Co3O4(111) and 1.1 for CoO(111) Electron energy loss (EELS) spectra for Co_3O_4(111) indicate interband transitions at ~2.1 and 3.0 eV, while only a single interband transition near 2.0 eV is observed for CoO(111) Low energy electron diffraction (LEED) data for Co_3O_4(111) indicate twinning during growth, in contrast to the LEED data for CoO(111) For Co_3O_4(111) films of less than 20 A average thickness, however, XPS, LEED and EELS data are similar to those of CoO(111) XPS data indicate that both Co oxide phases are hydroxylated at all thicknesses. The two phases are moreover found to be thermally stable to at least 900 K in UHV, while ex situ atomic force microscopy measurements of Co_3O_4(111)/Ru(0001) indicate an average surface roughness below 1 nm. Electrical measurements indicate that Co_3O_4(111)/Ru(0001) films exhibit dielectric breakdown at threshold voltages of ~1 MV cm^ 1) Collectively, these data show that the growth procedures yield Co_3O_4(111) films with topographical and electrical characteristics that are suitable for a variety of advanced device applications.
author_names: Opeyemi Olanipekun

Chad Ladewig

Jeffry A Kelber

M D Randle

J Nathawat

C -P Kwan

Jonathan P Bird

Priyanka Chakraborti

Peter A Dowben

Tao Cheng

William A Goddard
title: Epitaxial growth of cobalt oxide phases on Ru(0001) for spintronic device applications
year: 2017

abstract: In this current work, we report the synthesis of transition metal (TM) Cobalt(Co) doped ZnO (Zn1 x Cox O where x 0.01, 0.05, 0.1) powders by solution combustion process using urea (NH2CONH2) as fuel. The synthesized powders were characterized by XRD for phase anlalysis and SEM for microstructure. The powder XRD patterns of the samples confirms the formation of polycrystalline ZnO of hexagonal wurtzite structure by comparing with the standard peaks of JCPDS card no 36 1451. The crystallite size of the powder ranges from 18 30nm when calculated by Scherrer formula. SEM images shows the leaf like ZnO particales of thikness 60nm with 400 600nm length. Keywords Combustion, Zinc Nitrate, Cobalt Nitrate, Urea.
author_names: J Venkatesh B

Baburao N Sherikar
title: Synthesis of Cobalt (Co) doped ZnO Spintronic Nano Powders by Solution Combustion Method and Their Characterization
year: 2017

author_names: Biju Mani Rajbongshi
title: Investigation on mixed phase cobalt doped ZnO as novel spintronic photocatalyst and the engineering scheme for enhancing its performance
year: 2016

abstract: Abstract DFT based structural optimizations and cohesive energies of novel Co based Heusler compounds confirm the stability of these alloys in L21 phase (Cu2MnAl prototype) Later, the equilibrium lattice constants are predicted. While defining the electronic structure, the modified Beckhe Johnson scheme for exchange correlations predicted more efficient results than the generalized gradient approximation and onsite Hubbard approximation. Calculated band structure and densities of states together with spin magnetic moments designate the half metallic character of these alloys. The elastic constants are calculated to define the mechanical stability and ductile nature of these alloys. The ferromagnetic spin moments amount to an integral value of 3mB for each system with a maximum contribution from transition metal cobalt atom. Present study opens a way out for the potential application of these alloys as spintronic materials.
author_names: Shakeel Ahmad Khandy

Ishtihadah Islam

Dinesh Chandra Gupta

Amel Laref
title: Full Heusler alloys (Co2TaSi and Co2TaGe) as potential spintronic materials with tunable band profiles
venue: Journal of Solid State Chemistry
year: 2019

abstract: Abstract The inexorable trend of next generation spintronics is to develop smaller, lighter, faster, and more energy efficient devices. Ultimately, spintronics driven by free energy, for example, solar power, is imperative. Here, a prototype photovoltaic spintronic device with an optical magneto electric tricoupled photovoltaic/magnetic thin film heterojunction, where magnetism can be manipulated directly by sunlight via interfacial effect, is proposed. The magnetic anisotropy is reduced evidenced by the out of plane ferromagnetic resonance (FMR) field change of 640.26 Oe under 150 mW cm 2 illumination via in situ electron spin resonance (ESR) method. The transient absorption analysis and the first principles calculation reveal that the photovoltaic electrons doping in the cobalt film alter the band filling of this ferromagnetic film. The findings provide a new path of electron doping control magnetism and demonstrate an optical magnetic dual controllable logical switch with limited energy supply, which may further transform the landscape of spintronics research.
author_names: Yifan Zhao

Shishun Zhao

Lijun Wang

Ziyao Zhou

Junxue Liu

Tai Min

Bin Peng

Zhongqiang Hu

Shengye Jin

Ming Liu
title: Sunlight Control of Interfacial Magnetism for Solar Driven Spintronic Applications
venue: Advanced science
year: 2019

author_names: Luis Serrano-Ramon
title: Cobalt nanostructures grown by focused electron beam induced deposition for future spintronic applications
year: 2014

abstract: El objetivo de esta tesis consiste en la creacion de nuevas nanoestructuras magneticas basadas en cobalto crecido por deposicion inducida por haz focalizado de electrones (FEBID) para su implementacion en futuros dispositivos de espintronica basados en la conduccion de paredes de dominio. Estos depositos han demostrado en el pasado poseer alta pureza (mas de un 90% at. de cobalto) poco comun en estructuras crecidas mediante esta tecnica. Ademas, los nanohilos crecidos mediante FEBID presentan una buena conduccion de paredes de dominio, caracteristica necesaria en este tipo de dispositivo. Estas cualidades, junto con la enorme versatilidad de los procesos de FEBID, permiten la creacion de estructurabi y tridimensionales en un unico paso,imposibles de conseguir mediante metodos tradicionales de litografia. Con objeto de crear estructuras competitivas con la tecnologia actual es necesario mejorar nuestro conocimiento sobre las estructuras magneticas creadas por este metodo asi como reducir sus dimensiones.En esta trabajo la investigacion se ha centrado en cuatro campos bien diferenciados: la mejora en la resolucion lateral de los depositos (previo a este trabajo 150 nm) mediante el estudio de los diferentes parametros involucrados en el crecimiento y el desarrollo de un nuevo protocolo para la creacion de estructuras tridimensionales funcionales, el estudio mediante imagen de la estructura magnetica de nanohilos crecidos por este metodo y de las paredes de dominio que albergan, estudiar la dinamica del movimiento de paredes de dominio en estas nanoestructuras y modificar de manera controlada las propiedades magneticas de los depositos mediante irradiacion global o local de galio.
author_names: Luis Enrique Serrano Ramon
title: Cobalt nanostructures grown by focused electron beam induced deposition for future spintronic applications
year: 2014

abstract: This article reports the fabrication and characterization of thin films of pure and cobalt doped ZnO (Co at 4% and 7% a transparent diluted magnetic semiconductor (DMS) grown on 'Si' and glass substrates by RF magnetron sputtering technique. The crystalline structure and phase of the grown thin films were analyzed by using X ray diffraction (XRD) method which confirmed the hexagonal wurtzite structure of the ZnO with slight lattice strain and change in orientation of the planes. The XRD also confirmed that, the films exhibit prominent peaks of (1 0 1) and (1 0 3) with polycrystalline nature. The morphology of the grown thin films was investigated by scanning electron microscopy (SEM) which confirmed the variation of micro structure and size of the polycrystalline film's surface. The energy dispersive X ray spectra (EDS) from SEM have confirmed the presence of constituent elements in the films and concentration (in of each element. The crystalline properties and morphology of the film's cross section were studied by high resolution transmission electron microscopy (HR TEM) The average thickness of the films was found to be about 600 nm from the cross section electron microscopic images. The selected area electron diffraction (SAED) pattern from TEM was recorded for the Co (7% doped ZnO film which has good polycrystalline quality. The optical transmittance of the films coated on corning glass substrates was investigated by UV Visible spectrophotometer for pure, 4% and 7% Co doped ZnO films, which revealed the optical transparency of 85% 75% and 65% respectively. The room temperature ferromagnetism of the doped films was analysed by vibrating sample magnetometry and magneto optic Kerr effect. It was found that the ferromagnetic behaviour of films increases with 'Co' content and the results were discussed in detail.
author_names: R Siddheswaran

Rostislav Medlin

C Esther Jeyanthi

Srinivasan Gokul Raj

Ramalinga Viswanathan Mangalaraja
title: Structural, morphological, optical and magnetic properties of RF sputtered Co doped ZnO diluted magnetic semiconductor for spintronic applications
venue: Applied Physics A
year: 2019

abstract: Cobalt doped Mn2O3 nanoparticles have been synthesized by chemical route. The structural properties were analyzed by X ray diffraction (XRD) and scanning electron microscope (SEM) analysis. The SEM image shows that the nanoclusters having spherical geometry. The optical properties were analyzed by ultraviolet visible (UV Vis) and Fourier transform infrared (FTIR) spectroscopy. UV Vis spectra illustrates that Co doped Mn2O3 nanosystem acquire blue shift from bulk value (2.5 eV) The chemical composition and purity of the samples were examined using energy dispersive analysis of X ray spectroscopy (EDAX) Magnetic properties were studied using electron of 3.5mB shows the enhancement in magnetic transition temperature (Tc) of Mn2O3 nanosystem due to the incorporation of cobalt ions. (c) 2013 Published by Elsevier Ltd. Selection and/or peer review under responsibility of SMND.
author_names: K S Pugazhvadivua

K Ramachandranb

K Tamilarasana
title: ScienceDirect Spintronic Materials Nanostructures and Devices SMND 2011 Synthesis and Characterization of Cobalt doped Manganese Oxide Nanoparticles by Chemical Route
year: 2013