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Magnetostrictive thin films for microwave spintronics.

Parkes DE, Shelford LR, Wadley P, Holý V, Wang M, Hindmarch AT, van der Laan G, Campion RP, Edmonds KW, Cavill SA, Rushforth AW - Sci Rep (2013)

Bottom Line: Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies.Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths.Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films.

View Article: PubMed Central - PubMed

Affiliation: School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom.

ABSTRACT
Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies. Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths. Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films. We report the development of epitaxial thin films of Galfenol (Fe81Ga19) with magnetostriction as large as the best reported values for bulk material. This allows the magnetic anisotropy and microwave resonant frequency to be tuned by voltage-induced strain, with a larger magnetoelectric response and a narrower linewidth than any previously reported Galfenol thin films. The combination of these properties make epitaxial thin films excellent candidates for developing tunable devices for magnetic information storage, processing and microwave communications.

No MeSH data available.


Related in: MedlinePlus

Structural and magnetic properties.(a) X-ray 2θ/ω scan (main graph) and the ω scan (left inset) and ϕ scan (right inset) of the MBE-grown thin Fe81Ga19 film. The points and lines denote the measured data and the fits, respectively. (b) The change in the transverse resistivity measured as a function of the magnetic field applied in the plane of the device along the [100]/[010] directions with tensile strain, ε = εxx−εyy applied. (c) Magnetic hysteresis loop extracted from the data in (b) using the AMR formula for transverse resistivity and magnetic field applied along [100]. (d) Schematic diagram of the Hall bar/piezoelectric device layout showing directions of the tensile strain, εxx, the electrical current, j, and the crystalline directions of the Fe81Ga19 film.
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f1: Structural and magnetic properties.(a) X-ray 2θ/ω scan (main graph) and the ω scan (left inset) and ϕ scan (right inset) of the MBE-grown thin Fe81Ga19 film. The points and lines denote the measured data and the fits, respectively. (b) The change in the transverse resistivity measured as a function of the magnetic field applied in the plane of the device along the [100]/[010] directions with tensile strain, ε = εxx−εyy applied. (c) Magnetic hysteresis loop extracted from the data in (b) using the AMR formula for transverse resistivity and magnetic field applied along [100]. (d) Schematic diagram of the Hall bar/piezoelectric device layout showing directions of the tensile strain, εxx, the electrical current, j, and the crystalline directions of the Fe81Ga19 film.

Mentions: The crystal structure of our MBE-grown thin film was confirmed by x-ray diffraction (XRD). Similar to the case of Fe/GaAs(001)23, the (001) planes of the Fe81Ga19 film are parallel to those of the substrate, with a lattice constant which is approximately half that of GaAs. The 2θ/ω scan shown in figure 1(a) was fitted by standard XRD software using a model of a single perfect layer on a semi-infinite substrate. From the fit we determined the thickness of the layer to be t = 21.0 ± 0.2 nm and the vertical strained lattice parameter nm, representing a lattice mismatch of 4.6%, where is the lattice parameter along the growth axis for the Fe81Ga19 film, and  nm corresponds to half the GaAs substrate lattice parameter. The clear fourfold symmetry observed in the ϕ scan of the Fe81Ga19 (right inset to Fig. 1(a)) confirms the epitaxial relationship between the film and the substrate. The presence of the sharp majority component in the ω-scan (left inset to Fig. 1(a)) indicates the high quality of the mean crystal structure. The minor broad component is likely caused by localised, point like defects.


Magnetostrictive thin films for microwave spintronics.

Parkes DE, Shelford LR, Wadley P, Holý V, Wang M, Hindmarch AT, van der Laan G, Campion RP, Edmonds KW, Cavill SA, Rushforth AW - Sci Rep (2013)

Structural and magnetic properties.(a) X-ray 2θ/ω scan (main graph) and the ω scan (left inset) and ϕ scan (right inset) of the MBE-grown thin Fe81Ga19 film. The points and lines denote the measured data and the fits, respectively. (b) The change in the transverse resistivity measured as a function of the magnetic field applied in the plane of the device along the [100]/[010] directions with tensile strain, ε = εxx−εyy applied. (c) Magnetic hysteresis loop extracted from the data in (b) using the AMR formula for transverse resistivity and magnetic field applied along [100]. (d) Schematic diagram of the Hall bar/piezoelectric device layout showing directions of the tensile strain, εxx, the electrical current, j, and the crystalline directions of the Fe81Ga19 film.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3713564&req=5

f1: Structural and magnetic properties.(a) X-ray 2θ/ω scan (main graph) and the ω scan (left inset) and ϕ scan (right inset) of the MBE-grown thin Fe81Ga19 film. The points and lines denote the measured data and the fits, respectively. (b) The change in the transverse resistivity measured as a function of the magnetic field applied in the plane of the device along the [100]/[010] directions with tensile strain, ε = εxx−εyy applied. (c) Magnetic hysteresis loop extracted from the data in (b) using the AMR formula for transverse resistivity and magnetic field applied along [100]. (d) Schematic diagram of the Hall bar/piezoelectric device layout showing directions of the tensile strain, εxx, the electrical current, j, and the crystalline directions of the Fe81Ga19 film.
Mentions: The crystal structure of our MBE-grown thin film was confirmed by x-ray diffraction (XRD). Similar to the case of Fe/GaAs(001)23, the (001) planes of the Fe81Ga19 film are parallel to those of the substrate, with a lattice constant which is approximately half that of GaAs. The 2θ/ω scan shown in figure 1(a) was fitted by standard XRD software using a model of a single perfect layer on a semi-infinite substrate. From the fit we determined the thickness of the layer to be t = 21.0 ± 0.2 nm and the vertical strained lattice parameter nm, representing a lattice mismatch of 4.6%, where is the lattice parameter along the growth axis for the Fe81Ga19 film, and  nm corresponds to half the GaAs substrate lattice parameter. The clear fourfold symmetry observed in the ϕ scan of the Fe81Ga19 (right inset to Fig. 1(a)) confirms the epitaxial relationship between the film and the substrate. The presence of the sharp majority component in the ω-scan (left inset to Fig. 1(a)) indicates the high quality of the mean crystal structure. The minor broad component is likely caused by localised, point like defects.

Bottom Line: Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies.Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths.Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films.

View Article: PubMed Central - PubMed

Affiliation: School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom.

ABSTRACT
Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies. Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths. Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films. We report the development of epitaxial thin films of Galfenol (Fe81Ga19) with magnetostriction as large as the best reported values for bulk material. This allows the magnetic anisotropy and microwave resonant frequency to be tuned by voltage-induced strain, with a larger magnetoelectric response and a narrower linewidth than any previously reported Galfenol thin films. The combination of these properties make epitaxial thin films excellent candidates for developing tunable devices for magnetic information storage, processing and microwave communications.

No MeSH data available.


Related in: MedlinePlus