Morphology, structure, and magnetism of FeCo thin films electrodeposited on hydrogen-terminated Si(111) surfaces

Zarpellon, J.; Jurca, H. F.; Mattoso, N.; Klein, J. J.; Schreiner, W. H.; Ardisson, José D.; Macedo, W. A. A.; Mosca, D. H.

doi:10.1016/j.jcis.2007.08.032

Cited by 17 publications

(15 citation statements)

References 36 publications

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“…To measure the depth profile of the samples, XPS spectra were recorded after a series of sputtering time using Ar þ ions with 5 keV energy (Ar pressure, 2 Â 10 À8 mbar). 25 It is clear from XPS analysis that Fe is partially oxidized in the film and Co mainly in metallic state, it is due to larger resistance for oxidation of Co than Fe, in accordance with earlier observation. Resistivity and magnetoresistance measurements were carried out in Van der Pauw geometry in a commercial Lakeshore system.…”

Section: Methodssupporting

confidence: 90%

“…The estimation of the actual FeCo fraction and film thickness was performed using RUMP simulation code. 25,26 The CoO formation is expected due to oxidation of Co due to chemical reaction at the surface. Glancing angle x-ray diffraction (GAXRD) measurements were carried out using Cu Ka radiation (k ¼ 1.5406 Å ) at grazing incidence of 1 at a scan rate of 0.03 deg/s.…”

Section: Methodsmentioning

confidence: 99%

“…X-ray photoelectron spectroscopy (XPS) measurements were carried out to evaluate the chemical state analysis, using a SPECS system with a base pressure of 2 Â 10 À9 mbar. 25,27 With reference to the literature data, it is easy to realize that Fe at the surface is present in the oxidized state due to chemical reaction with oxygen. The binding energy scale was calibrated using C1s peak (284.6 eV) to avoid energy shift due to charging effects.…”

Section: Methodsmentioning

confidence: 99%

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Role of Coulomb blockade and spin-flip scattering in tunneling magnetoresistance of FeCo-Si-O nanogranular films

Kumar¹,

Ghosh²,

Bürger³

et al. 2011

Journal of Applied Physics

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In this work, we report the effect of FeCo atomic fraction (0.33 < x < 0.54) and temperature on the electrical, magnetic, and tunneling magnetoresistance (TMR) properties of FeCo-Si-O granular films prepared by atom beam sputtering technique. Glancing angle x-ray diffraction and TEM studies reveal that films are amorphous in nature. The dipole–dipole interactions (particle–matrix mixing) is evident from zero-field cooled and field-cooled magnetic susceptibility measurements and the presence of oxides (mainly Fe-related) is observed by x-ray photoelectron spectroscopy analysis. The presence of Fe-oxides is responsible for the observed reduction of saturation magnetization and rapid increase in coercivity below 50 K. TMR has been observed in a wide temperature range, and a maximum TMR of −4.25% at 300 K is observed for x = 0.39 at a maximum applied field of 60 kOe. The fast decay of maximum TMR at high temperatures and lower TMR values at 300 K when compared to PFeCo2/(1+PFeCo2), where PFeCo is the spin polarization of FeCo are in accordance with a theoretical model that includes spin-flip scattering processes. The temperature dependent study of TMR effect reveals a remarkably enhanced TMR at low temperatures. The TMR value varies from −2.1% at 300 K to −14.5% at 5 K for x = 0.54 and a large MR value of −18.5% at 5 K for x = 0.39 is explained on the basis of theoretical models involving Coulomb blockade effects. Qualitatively particle–matrix mixing and the presence of Fe-oxides seems to be the source of spin-flip scattering, responsible for fast decay of TMR at high temperatures. A combination of higher order tunneling (in Coulomb blockade regime) and spin-flip scattering (high temperature regime) explains the temperature dependent TMR of these films.

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Section: Methodssupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Role of Coulomb blockade and spin-flip scattering in tunneling magnetoresistance of FeCo-Si-O nanogranular films

Kumar¹,

Ghosh²,

Bürger³

et al. 2011

Journal of Applied Physics

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“…Our work finally demonstrates that high saturation magnetization, low coercivity and high electrical resistivity FeCo thin films can be achieved by thermal evaporation from properly set mechanical alloying powder. [3,4,5]. The methods used require either a reliable control of the composition and structure in designing the magnetic functionality of these materials or, such as the case of underlayer insertion, necessitate further processing and then, require more time and cost.…”

Section: Microstructural Electrical and Magnetic Properties Ofmentioning

confidence: 99%

Microstructural, electrical and magnetic properties of Fe35Co65 thin films grown by thermal evaporation from mechanically alloyed powders

et al. 2014

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We present a detailed study of the microstructural, electrical and magnetic properties of Fe 35 Co 65 thin films deposited by thermal evaporation using nanocrystalline mixture. The nanocrystalline Fe 35 Co 65 powder was prepared by mechanical alloying process using high energy ball milling and then carefully studied. Good homogeneity, purity and stoichiometry were demonstrated in the powder composed of 25 nm mean crystallite size. Microstuctural analysis of Fe 35 Co 65 thin films ranging from 9 to 50 nm deposited on Si (001) shows that the stoichiometry is conserved over the whole thickness range and that (110) texture forms as the film thickness increases. Our work finally demonstrates that high saturation magnetization, low coercivity and high electrical resistivity FeCo thin films can be achieved by thermal evaporation from properly set mechanical alloying powder.

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“…2 Many researches have produced nanocrystalline CoFe alloys thin films by different techniques and studied their microstructures and magnetic properties. [7][8][9] Electrochemical deposition is suitable method to produce such a nanocrystalline structure and is normally preferred with respect to sputtering. 2 Osaka et al 4 electrodeposited Co 65 Fe 23 Ni 12 thin film with very good soft magnetic properties from a low pH level (2.8) and additive-free bath.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Evaluation of Nanocrystalline Cobalt-Iron-Nickel Thin Films Electrodeposited From Citrate-Free and Citrate-Added Baths

Mehrizi

Sohi

Ebrahimi

2012

Int. J. Mod. Phys. Conf. Ser.

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The microstructures of nanocrystalline CoFeNi thin films in direct current electrodeposition, under various processing conditions, have comparatively been investigated. Morphological studies by SEM showed that CoFeNi films plated from the sodium citrate-added baths were more uniform and denser than those deposited from the conventional citrate-free baths. Energy dispersive spectroscopy (EDS) showed the anomalous behaviors in electrodeposition of CoFeNi films from both citrate-added and citrate-free baths. It was also noticed that addition of 10g/L sodium citrate in the bath strongly decreases the iron content and increases nickel contents of the deposit. Addition of citrate up to 50g/L in the bath has reverse effect on the film composition. Further addition of sodium citrate appears to have no or little effect on the film composition. Addition of sodium citrate to the bath has no significant affect on the cobalt content of the deposit. XRD analyses showed that all CoFeNi films were nanocrystalline and their average grain sizes, estimated by Scherrer formula, were below 80nm. It was also noticed that FCC and BCC phases could be co-deposited in electroplated CoFeNi films by controlling the bath composition and/or the plating conditions.

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Morphology, structure, and magnetism of FeCo thin films electrodeposited on hydrogen-terminated Si(111) surfaces

Cited by 17 publications

References 36 publications

Role of Coulomb blockade and spin-flip scattering in tunneling magnetoresistance of FeCo-Si-O nanogranular films

Role of Coulomb blockade and spin-flip scattering in tunneling magnetoresistance of FeCo-Si-O nanogranular films

Microstructural, electrical and magnetic properties of Fe35Co65 thin films grown by thermal evaporation from mechanically alloyed powders

Microstructural Evaluation of Nanocrystalline Cobalt-Iron-Nickel Thin Films Electrodeposited From Citrate-Free and Citrate-Added Baths

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