Two-dimensional arrays of vertically packed spin-valves with picoTesla sensitivity at room temperature

AbstractA new device architecture using giant magnetoresistive sensors demonstrates the capability to detect very low magnetic fields on the pT range. A combination of vertically packed spin-valve sensors with two-dimensional in-plane arrays, connected in series and in parallel, delivers a final detection level of 360 pT/$$\sqrt{Hz}$$ Hz at 10 Hz at room temperature. The device design is supported by an analytical model developed for a vertically packed spin-valve system, which takes into account all magnetic couplings present. Optimization concerning the spacer thickness and sensor physical dimensions depending on the number of pilled up spin-valves is necessary. To push the limits of detection, arrays of a large number of sensing elements (up to 440,000) are patterned with a geometry that improves sensitivity and in a configuration that reduces the resistance, leading to a lower noise level. The final device performance with pT detectivity is demonstrated in an un-shielded environment suitable for detection of bio-signals.

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A new device architecture based on two dimensional van der Waals heterostructures

2017 IEEE 12th International Conference on ASIC (ASICON) ◽

10.1109/asicon.2017.8252565 ◽

2017 ◽

Author(s):

Zhongxun Guo ◽

Wu Zan ◽

Peng Zhou ◽

Wenzhong Bao ◽

David Wei Zhang

Keyword(s):

Van Der Waals ◽

Two Dimensional ◽

Van Der Waals Heterostructures ◽

New Device ◽

Device Architecture

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MAGNETORESISTANCE IN NANO-SCALE NiO-CONTAINING Co/Cu/Co SPIN VALVES

International Journal of Modern Physics B ◽

10.1142/s0217979205031341 ◽

2005 ◽

Vol 19 (15n17) ◽

pp. 2574-2579 ◽

Cited By ~ 2

Author(s):

A. M. ZHANG ◽

X. S. WU ◽

L. SUN ◽

A. HU

Keyword(s):

Room Temperature ◽

Annealing Temperature ◽

Growth Parameters ◽

Coupling Effect ◽

Spin Valve ◽

Interface Roughness ◽

Spin Valves ◽

X Ray ◽

X Ray Scattering

A series of NiO -containing Co/Cu/Co spin valves with the thickness Co of 5 nm and Cu of 2 nm were fabricated by magnetron sputtering technique with different growth parameters. NiO layer with the thickness of 40 nm is used as a coupling layer. Magnetoresistance (MR) of the spin valve with NiO layer under the bottom of Co/Cu/Co (BSV) is larger than that of the spin valve with NiO layer at the top of Co/Cu/Co (TSV) at room temperature. The MR values can be improved with decreasing the sputtering rate of copper layer. The studies by in-situ grazing incident X-ray scattering on the annealing temperature dependence of MR show that the decrease of the interface roughness between Co and NiO may increase the MR value, while the decrease of the coupling effect between NiO and Co decreases the MR value.

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Huge magnetoresistance in topological insulator spin-valves at room temperature

Scientific Reports ◽

10.1038/s41598-021-91242-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Peng Tseng ◽

Jyun-Wei Chen ◽

Wen-Jeng Hsueh

Keyword(s):

Thin Film ◽

Topological Insulators ◽

Room Temperature ◽

Spin Valve ◽

Spin Valves ◽

Spintronic Devices ◽

Spin Polarized ◽

Controlled Potential ◽

Gate Potential ◽

Mr Effect

AbstractTopological insulators (TI) have extremely high potential in spintronic applications. Here, a topological insulators thin-film (TITF) spin valve with the use of the segment gate-controlled potential exhibits a huge magnetoresistance (MR) value higher than 1000% at room temperature which is more than 50 times the MR of typical topological insulators (TI) spin-valves. A high spin-polarized current is provided by the band structure generated by the tunable segment potential. The results reveal a very large resistance difference between the parallel and antiparallel configurations. The MR effect is strongly influenced by the thin-film thickness, the gate potential, the gate size, and the distribution. The proposed results will help to not only improve the room-temperature performance of the spin-valves but also enhance the applications of magnetic memories and spintronic devices.

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Magnetoresistance Effect in NiFe/BP/NiFe Vertical Spin Valve Devices

Advances in Condensed Matter Physics ◽

10.1155/2017/9042823 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 7

Author(s):

Leilei Xu ◽

Jiafeng Feng ◽

Kangkang Zhao ◽

Weiming Lv ◽

Xiufeng Han ◽

...

Keyword(s):

Thin Film ◽

Room Temperature ◽

Transition Metal Dichalcogenides ◽

Spin Valve ◽

Layered Materials ◽

Two Dimensional ◽

Magnetoresistance Effect ◽

2D Layered Materials ◽

Metal Dichalcogenides ◽

Valve Effect

Two-dimensional (2D) layered materials such as graphene and transition metal dichalcogenides are emerging candidates for spintronic applications. Here, we report magnetoresistance (MR) properties of a black phosphorus (BP) spin valve devices consisting of thin BP flakes contacted by NiFe ferromagnetic (FM) electrodes. The spin valve effect has been observed from room temperature to 4 K, with MR magnitudes of 0.57% at 4 K and 0.23% at 300 K. In addition, the spin valve resistance is found to decrease monotonically as temperature is decreased, indicating that the BP thin film works as a conductive interlayer between the NiFe electrodes.

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Polymorphic gallium for active resonance tuning in photonic nanostructures: from bulk gallium to two-dimensional (2D) gallenene

Nanophotonics ◽

10.1515/nanoph-2020-0314 ◽

2020 ◽

Vol 9 (14) ◽

pp. 4233-4252

Author(s):

Yael Gutiérrez ◽

Pablo García-Fernández ◽

Javier Junquera ◽

April S. Brown ◽

Fernando Moreno ◽

...

Keyword(s):

Optical Properties ◽

Room Temperature ◽

Phase Change Materials ◽

Two Dimensional ◽

Active Materials ◽

Promising Candidate ◽

Plasmonic Structures ◽

Resonance Tuning ◽

The Many ◽

Optical Behavior

AbstractReconfigurable plasmonics is driving an extensive quest for active materials that can support a controllable modulation of their optical properties for dynamically tunable plasmonic structures. Here, polymorphic gallium (Ga) is demonstrated to be a very promising candidate for adaptive plasmonics and reconfigurable photonics applications. The Ga sp-metal is widely known as a liquid metal at room temperature. In addition to the many other compelling attributes of nanostructured Ga, including minimal oxidation and biocompatibility, its six phases have varying degrees of metallic character, providing a wide gamut of electrical conductivity and optical behavior tunability. Here, the dielectric function of the several Ga phases is introduced and correlated with their respective electronic structures. The key conditions for optimal optical modulation and switching for each Ga phase are evaluated. Additionally, we provide a comparison of Ga with other more common phase-change materials, showing better performance of Ga at optical frequencies. Furthermore, we first report, to the best of our knowledge, the optical properties of liquid Ga in the terahertz (THz) range showing its broad plasmonic tunability from ultraviolet to visible-infrared and down to the THz regime. Finally, we provide both computational and experimental evidence of extension of Ga polymorphism to bidimensional two-dimensional (2D) gallenene, paving the way to new bidimensional reconfigurable plasmonic platforms.

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