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Taiebeh Tahmasebi

Bio: Taiebeh Tahmasebi is an academic researcher from GlobalFoundries. The author has contributed to research in topics: Layer (electronics) & Tunnel magnetoresistance. The author has an hindex of 14, co-authored 39 publications receiving 699 citations. Previous affiliations of Taiebeh Tahmasebi include Katholieke Universiteit Leuven & IMEC.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a simple method based on solid state ball-milling and calcinations of nitrate precursors and citric acid was used to synthesize MnFe2O4 ferrites.

130 citations

Patent
17 Jun 2014
TL;DR: In this paper, a spin transfer torque magnetic random access memory (STTMRAM) element with a perpendicular magnetic anisotropy (PMA) was disclosed, where the alternating layers of a first metal and a second metal are repeated n times with, 2 <=n<=20
Abstract: The disclosed technology generally relates to semiconductor devices, and more particularly spin transfer torque magnetic random access memory (STTMRAM) elements having perpendicular magnetic anisotropy (PMA) In one aspect, a magnetic element comprises a metal underlayer and a seed layer on the underlayer, the seed layer comprising alternating layers of a first metal and a second metal The alternating layers of a first metal and a second metal are repeated n times with, 2<=n<=20 Also a spin transfer torque magnetic random access memory element is disclosed having a perpendicular magnetic orientation comprising a metal underlayer on a substrate, a seed layer on the metal underlayer; the seed layer comprising alternating layers of a first metal and a second metal, a magnetic tunnel junction (MTJ) element with a perpendicular orientation including: a reference layer formed on the seed layer, a tunnel barrier layer formed on the reference layer, a storage layer formed on the tunnel barrier layer and a top electrode and a bottom electrode

88 citations

Journal ArticleDOI
TL;DR: In this article, a dual pseudo spin valve with perpendicular magnetic anisotropy is investigated for spin transfer torque (STT) switching, which consists of two free layers and one reference layer, and all are based on Co/Pd multilayer.
Abstract: A novel multi-bit dual pseudo spin valve with perpendicular magnetic anisotropy is investigated for spin transfer torque (STT) switching. The structure consists of two free layers and one reference layer, and all are based on Co/Pd multilayer. STT switching of the multi-bit device shows distinct four resistance levels. The selection of intrinsic properties of each ferromagnetic layer can be controlled for distinct separation of the resistance levels as well as the respective STT switching current. Reversible transitions between different states can be achieved by a pulsed current, in which its critical value is found to be linearly dependent on pulse duration.

52 citations

Journal ArticleDOI
TL;DR: A pronounced Fano resonance (FR) is observed for the fabricated nano-discs with inter-disk gaps of around 18 nm during light irradiation at normal incidence, and the near-field energy spatial distribution can be flexibly tuned by the polarization direction.
Abstract: Arrays of planar symmetric gold quadrumers consisting of a central nano-disc surrounded by three similar nano-discs belonging to the D3h point group were designed and fabricated. Since the geometrical configuration of quadrumers is the same as planar trigonal molecules, nano-discs can play the roles of artificial atoms to study the coupling trends among them. The plasmonic properties of the nano-disc structures are investigated by reflection spectrum measurement and finite-difference time-domain calculation with good agreement. Plasmon interaction among the nano-discs is also studied via a mass‐spring coupled oscillator model. A pronounced Fano resonance (FR) is observed for the fabricated nano-discs with inter-disk gaps of around 18 nm during light irradiation at normal incidence. Although the obtained FR is independent of the excitation polarization, the near-field energy spatial distribution can be flexibly tuned by the polarization direction. This has potential applications in nano-lithography, optical switching and nonlinear spectroscopy. (Some figures in this article are in colour only in the electronic version)

48 citations

Proceedings ArticleDOI
01 Dec 2014
TL;DR: In this paper, the inner synthetic anti-ferromagnetic (iSAF) pinned layer in combination with ultra-smooth bottom electrode (roughness 0.5 A) was yielded to vertically scaled 11nm thick Co/Ni p-MTJ stack with excellent magnetic properties.
Abstract: Excellent tunnel magneto resistance (TMR) values of 143% at resistance-area products (RA) of 4.7 Ωµm2 from 11nm thin Co/Ni based perpendicular magnetic tunnel junctions (p-MTJ) was achieved. Engineered wetting layer (WL), seed layer (SL) and the introduction of newly designed inner synthetic anti-ferromagnetic (iSAF) pinned layer in combination with ultra-smooth bottom electrode (roughness 0.5 A) was yielded to vertically scaled 11nm thick Co/Ni p-MTJ stack with excellent magnetic properties. The introduction of iSAF layer demonstrates for the 1st time the free layer offset field controllability (< 100 Oe) of the spin-transfer-torque (STT) magnetic random access memory (MRAM) device down to 12 nm in diameter.

44 citations


Cited by
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Journal ArticleDOI
TL;DR: This article reviews spintronics based memories, in particular, magnetic random access memory (MRAM) in a systematic manner and discusses some of the future technologies that might help the industry to move beyond the conventional MRAM technology.

726 citations

Journal ArticleDOI
TL;DR: For SERS from carbon nanoparticles, it is found that the dielectric screening introduced by the nanoparticle can drastically redistribute the field enhancement associated with the Fano resonance and lead to a significantly modified SERS response compared to what would be anticipated from the bare nanocluster.
Abstract: While the far field properties of Fano resonances are well-known, clusters of plasmonic nanoparticles also possess Fano resonances with unique and spatially complex near field properties. Here we examine the near field properties of individual Fano resonant plasmonic clusters using surface-enhanced Raman scattering (SERS) both from molecules distributed randomly on the structure and from dielectric nanoparticles deposited at specific locations within the cluster. Cluster size, geometry, and interparticle spacing all modify the near field properties of the Fano resonance. For molecules, the spatially dependent SERS response obtained from near field calculations correlates well with the relative SERS intensities observed for individual clusters and for specific Stokes modes of a para-mercaptoaniline adsorbate. In all cases, the largest SERS enhancement is found when both the excitation and the Stokes shifted wavelengths overlap the Fano resonances. In contrast, for SERS from carbon nanoparticles we find that the dielectric screening introduced by the nanoparticle can drastically redistribute the field enhancement associated with the Fano resonance and lead to a significantly modified SERS response compared to what would be anticipated from the bare nanocluster.

472 citations

Journal ArticleDOI
TL;DR: It is shown that clusters with a hemicircular central disk surrounded by a circular ring of closely spaced, coupled nanodisks yield Fano-like and non-Fano- like spectra for orthogonal incident polarization orientations.
Abstract: Plasmonic clusters can support Fano resonances, where the line shape characteristics are controlled by cluster geometry. Here we show that clusters with a hemicircular central disk surrounded by a circular ring of closely spaced, coupled nanodisks yield Fano-like and non-Fano-like spectra for orthogonal incident polarization orientations. When this structure is incorporated into an uniquely broadband, liquid crystal device geometry, the entire Fano resonance spectrum can be switched on and off in a voltage-dependent manner. A reversible transition between the Fano-like and non-Fano-like spectra is induced by relatively low (∼6 V) applied voltages, resulting in a complete on/off switching of the transparency window.

339 citations

Journal ArticleDOI
TL;DR: It is demonstrated that light scattering by all-dielectric oligomers exhibits well-pronounced Fano resonances with strong suppression of the scattering cross section, which makes them promising for future applications in nanophotonics.
Abstract: We demonstrate that light scattering by all-dielectric oligomers exhibits well-pronounced Fano resonances with strong suppression of the scattering cross section. Our analysis reveals that this type of the Fano resonance originates from the optically induced magnetic dipole modes of individual high-dielectric nanoparticles. By comparing to the plasmonic analogues, we observe that Fano resonances in all-dielectric oligomers are less sensitive to structural variations, which makes them promising for future applications in nanophotonics.

316 citations

Journal ArticleDOI
TL;DR: Recently, a large number of experimental and theoretical works have revealed a variety of plasmonic nanostructures with the capabilities of Fano resonance (FR) generation as mentioned in this paper, and more attention is given to the optical properties of PLASmonic oligomers due to the high potential of such structures in optical spectra engineering.
Abstract: Recently, a large number of experimental and theoretical works have revealed a variety of plasmonic nanostructures with the capabilities of Fano resonance (FR) generation. Among these structures, plasmonic oligomers consisting of packed metallic nanoelements with certain configurations have been of significant interest. Oligomers can exhibit FR independently of the polarization direction based on dipole–dipole antiparallel modes without the need to excite challenging high-order modes. The purpose of this review article is to provide an overview of recent achievements on FR of plasmonic nanostructures in recent years. Meanwhile, more attention is given to the optical properties of plasmonic oligomers due to the high potential of such structures in optical spectra engineering.

273 citations