Spatially resolving variations in giant magnetoresistance, undetectable with four-point probe measurements, using infrared microspectroscopy

Kelley, Chris S.; Thompson, Sarah; Illman, M. D.; Lefrançois, Stéphane; Dumas, Paul

doi:10.1063/1.4760282

Cited by 3 publications

(4 citation statements)

References 11 publications

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“…Not much later, and in the same line, Kubrakov and coworkers theoretically postulated the existence of this "intensity magneto-optical effect" in GMR materials [31]. This discovery set up the connection between Optics and Spintronics and, since then, the MRE has been used to optically probe (therefore without the need of electrical contacts) the magnetotransport properties of a variety of spintronic devices and systems as well as to get a deeper understanding of the spin polarized electron properties of ferromagnets [32][33][34][35][36][37][38][39][40][41][42][43]. As an example in Figure 4 we present curves of magnetic field dependence of the resistivity and the optical response in the aforementioned spectral range for different spintronic systems.…”

Section: The Magneto Refractive Effect (Mre)mentioning

confidence: 90%

“…In spite of the technical challenge, different groups involved in the growth and study of spintronic systems soon explored the corresponding MRE properties. Apart from the Ni 80 Fe 20 /Cu/Co/Cu multilayers of Jacquet and Valet MRE pioneering work [13], various other systems have been studied in the near and far infrared range, such as Co/Cu [34,36,47,48] and CoFe/Cu multilayers [40,49,50,51]; Fe/Cr structures [52][53][54];…”

Section: Mre In Gmr Systemsmentioning

confidence: 99%

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Active photonic platforms for the mid-infrared to the THz regime using spintronic structures

Armelles

Cebollada

2020

Nanophotonics

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AbstractSpintronics and Photonics constitute separately two disciplines of huge scientific and technological impact. Exploring their conceptual and practical overlap offers vast possibilities of research and a clear scope for the corresponding communities to merge and consider innovative ideas taking advantage of each other’s potentials. As an example, here we review the magnetic field modification of the optical response of photonic systems fabricated out of spintronic materials, or in which spintronic components are incorporated. This magnetic actuation is due to the Magneto Refractive Effect (MRE), which accounts for the change in the optical constants of a spintronic system due to the magnetic field induced modification of the electrical resistivity. Due to the direct implication of conduction electrons in this phenomenon, this change in the optical constants covers from the mid-infrared to the THz regime. After introducing the non-expert reader into the spintronic concepts relevant to this work, we then present the MRE exhibited by a variety of spintronic systems, and finally show the different applications of this property in the generation of active spintronic-photonic platforms.

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Section: The Magneto Refractive Effect (Mre)mentioning

confidence: 90%

Section: Mre In Gmr Systemsmentioning

confidence: 99%

Active photonic platforms for the mid-infrared to the THz regime using spintronic structures

Armelles

Cebollada

2020

Nanophotonics

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“…Fe 3 O 4 /MgO(111) films of varying thickness (10,15,30,60 and 100 nm) were produced by molecular beam epitaxy (MBE) in York, using growth conditions based on those used by Gao et al [33]. The MBE chamber used to grow the films has a base pressure of 8 × 10 −10 mbar.…”

Section: Experimental Techniquesmentioning

confidence: 99%

“…We show that modelling the measured spectra transforms the MRE into a powerful technique for determining the underlying mechanisms of MR, as well as variations in MR, whilst also avoiding destructive, contact based electrical measurements [10]. Previously we have considered only metallic (Drude) conduction when constructing MRE models, in this work we develop a new, more complex dielectric function based on several conductivity contributions.…”

Section: Introductionmentioning

confidence: 99%

Investigating the magnetic field-dependent conductivity in magnetite thin films by modelling the magnetorefractive effect

Kelley

Naughton

Benson

et al. 2013

J. Phys.: Condens. Matter

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A model of the magnetorefractive effect is developed for metallic oxides which allows the MRE to be used to study the magnetic dependence of their transport and phononic properties. This model is successfully applied to Fe3O4 and compared to experiments on a series of magnetite thin films of varying thickness (10, 18, 37, 64 and 110 nm) deposited on MgO(111) substrates. Reflection spectra were modelled as a function of film thickness, calculated from the Fresnel equations using an Fe3O4 dielectric function consisting of Drude, hopping, phononic and d-s transition conductivity processes. The reflectivity spectra of the different thickness films are reasonably reproduced by the model and reveal that the Fe3O4 18.5 μm phonon peak is shifted to a shorter wavelength in the thin films, approaching the bulk value for t > 110 nm. The MRE spectra are modelled by introducing a magnetic field dependence to the hopping and phononic terms, where previous models have considered the magnetic dependence to be on the Drude term only. In addition, the position of the Fe3O4 18.5 μm phonon peak was also found to shift in energy in the applied magnetic field by 0.05 μm. These results demonstrate the potential for using the MRE technique for probing the underlying magnetoelectronic properties of thin film oxides in a quick and non-destructive way.

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Spatially resolved variations in reflectivity across iron oxide thin films

Kelley

Thompson

Gilks

et al. 2017

Journal of Magnetism and Magnetic Materials

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The spin polarising properties of the iron oxide magnetite (Fe3O4) make it attractive for use in spintronic devices, but its sensitivity to compositional and structural variations make it challenging to prepare reli- ably. Infrared microspectroscopy and modelling are used to determine the spatial variation in the chem- ical composition of three thin films of iron oxide; one prepared by pulsed laser deposition (PLD), one by molecular beam epitaxy (MBE) deposition of iron whilst simultaneously flowing oxygen into the chamber and one by flowing oxygen only once deposition is complete. The technique is easily able to distinguish between films which contain metallic iron and different iron oxide phases as well as spatial variations in composition across the films. The film grown by post-oxidising iron is spatially uniform but not fully oxi- dised, the film grown by simultaneously oxidising iron showed spatial variation in oxide composition while the film grown by PLD was spatially uniform magnetite

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Spatially resolving variations in giant magnetoresistance, undetectable with four-point probe measurements, using infrared microspectroscopy

Abstract: Thermally assisted-writing giant magnetoresistance with perpendicular magnetization J. Appl. Phys. 97, 10C511 (2005); 10.1063/1.1851954 Current-driven switching of exchange biased spin-valve giant magnetoresistive nanopillars using a conducting nanoprobe

Cited by 3 publications

References 11 publications

Active photonic platforms for the mid-infrared to the THz regime using spintronic structures

Active photonic platforms for the mid-infrared to the THz regime using spintronic structures

Investigating the magnetic field-dependent conductivity in magnetite thin films by modelling the magnetorefractive effect

Spatially resolved variations in reflectivity across iron oxide thin films

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