Superconducting quantum magnetic sensing

Vettoliere, A.; Silvestrini, P.; Granata, C.

doi:10.1016/b978-0-12-820566-2.00001-6

Cited by 11 publications

(8 citation statements)

References 65 publications

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“…Second, the two-magnon bound state component of the projections, which for the isotropic case almost overlaps with the solution depicted with the blue curve in the figure (see case A), now also moves upwards in energy (cases B-D) when anisotropy increases. Finally, contrary to the single magnon case where there is a single eigenstate of H that does overlap with the spin wave solution and, hence, has a well-defined character, now a large number of eigenstates with both Ising-and Bethe-type characters display finite but small overlap with the two-magnon sates (10).…”

Section: Results For a One-dimensional Toy Modelmentioning

confidence: 83%

“…From the experimental side, there are a bunch of experimental techniques that can be used to explore the magnetic order of thin films with magnetic anisotropy and, thus, the signatures of both single and multi-magnon processes. This includes x-ray magnetic circular dichroism [5] and its depth-resolved variants [6,7], neutron scattering, which has the additional advantage of direct access to the dispersion relation on the whole wave vector space [8,9], magnetometry using SQUID [10], Raman spectroscopy [11][12][13][14], ferromagnetic resonance (FMR) [15][16][17] or local techniques, such as spin-polarized scanning tunneling microscopy [18] and inelastic tunneling spectroscopy [19][20][21]. Interestingly, only recently the effect of magnons in atomically thin layers has been accessible experimentally through Raman scattering [22], allowing for instance to determine the optical selection rules established by the interplay between crystal symmetry, layer number, and magnetic states in CrI 3 .…”

Section: Introductionmentioning

confidence: 99%

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Spin wave excitations in low dimensional systems with large magnetic anisotropy

Delgado,

Otrokov,

Arnau

2024

J. Phys. Mater.

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The low-energy excitation spectrum of a two-dimensional ferromagnetic material is dominated by single-magnon excitations that show a gapless parabolic dispersion relation with the spin wave vector. This occurs as long as magnetic anisotropy and anisotropic exchange are negligible compared to isotropic exchange. However, to maintain magnetic order at finite temperatures in extended systems, it is necessary to have sizable anisotropy to open a gap in the spin wave excitation spectrum. We consider four real two-dimensional systems for which ferromagnetic order at finite temperature has been observed or predicted. Density functional theory calculations of the total energy differences for different spin configurations permit us to extract the relevant parameters and connect them with a spin Hamiltonian. The corresponding values of the Curie temperature are estimated using a simple model and found to be mostly determined by the value of the isotropic exchange. The exchange and anisotropy parameters are used in a toy model of finite-size periodic chains to study the low-energy excitation spectrum, including single-magnon and two-magnon excitations. At low energies, we find that single-magnon excitations appear in the spectrum together with two-magnon excitations. These excitations present a gap that grows particularly for large values of the magnetic anisotropy or anisotropic exchange, relative to the isotropic exchange.

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Section: Results For a One-dimensional Toy Modelmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Spin wave excitations in low dimensional systems with large magnetic anisotropy

Delgado,

Otrokov,

Arnau

2024

J. Phys. Mater.

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“…In recent years, the use of giant magneto resistance (GMR) biosensors for cancer detection has shown great promise in the biomedical field [2]. Furthermore, superconducting quantum interferometers are among the most sensitive detectors for magnetic flux and magnetic flux fields, with equivalent energy sensitivity close to the quantum limit [3], interferometers require low-temperature superconducting cooling, which complicates miniaturisation and portability. Compared with conventional magnetic field sensors, the surface acoustic wave (SAW) magnetic sensing technology has received widespread attention owing to its advantages of miniaturisation, high interference immunity, remarkable stability [4], and high measurement accuracy (up to 100 pT/Hz 0.5 [5]).…”

Section: Introductionmentioning

confidence: 99%

Highly sensitive surface acoustic wave magnetic field sensor based on the loss mechanism

Wu,

Cui,

Jia

et al. 2024

Smart Mater. Struct.

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Currently, the surface acoustic wave (SAW) magnetic field sensing technique utilises the SAW velocity/frequency mechanism of magnetoacoustic interaction as an indicator of the magnetic sensitivity mechanism. However, this method has low sensitivity and poor stability. To address this problem, a dynamic magnetoelastic coupling theoretical model is constructed to theoretically simulate the influence of the ∆E effect of magnetically sensitive thin films on SAW propagation attenuation. This study describes a high-sensitivity SAW magnetic field sensing mechanism based on magnetoacoustic attenuation. The simulation results show a clear relationship between the acoustic propagation loss and external magnetic field, indicating a structure-property relationship. An amorphous soft magnetic material (Fe90Co10)78Si12B10 was used as a magnetically sensitive thin film due to its high permeability, low coercivity (Hc), low hysteresis, ease of magnetisation and demagnetisation. SAW magnetosensitive device operating on a frequency of 200 MHz has been experimentally developed using a standard semiconductor photolithography process. A SiO2 layer was deposited on a 36° YX-LiTaO3 substrate as a waveguide, and a (Fe90Co10)78Si12B10 layer was on the top of the propagation area as a magnetosensitive film. The experimental results showed that the acoustic loss change due to the magnetic field variation was 4.63 dB within a magnetic field range of 0 Oe to ±10 Oe, which agreed with the theoretical results. The sensor had a sensitivity of 0.7546 dB/Oe within the range of 0 to 4 Oe and the lower detection limit of magnetic fields was 0.272 Oe, low hysteresis error of 0.54%, multiple repeatability error of 0.13%, excellent repeatability and stability were achieved in the experiments from the developed sensing device.

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“…As is known, superconductivity is the most extraordinary manifestation of quantum mechanics at the macroscopic level, and superconducting devices are consolidated and tested examples of quantum technologies [ 1 ]. In particular, superconducting quantum interference devices (SQUID) are the most sensitive magnetic field and flux sensors, reaching an energy sensitivity per band unit equal to a few Plank constants [ 4 , 5 , 6 , 7 , 8 ]. Such extraordinary sensitivity lies in its quantum nature and in particular in the fact that a macroscopic quantity such as voltage or a current of the order of a few tens of mV or µA is linked to one of the constants of quantum mechanics, i.e., the elementary magnetic flux quantum Φ₀ = h/2e, where h is the Planck’s constant and e is the charge of the electron.…”

Section: Introductionmentioning

confidence: 99%

“…However, the current applications that require very high sensitivity still use SQUID based sensors. Among these, it is worth mentioning the biomagnetism, quantum computing, geophysics, magnetic microscopy, nanomagnetism, non-destructive analysis of materials, and fundamental physics experiments [ 5 , 6 , 7 , 8 , 14 , 15 , 16 , 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Highly Sensitive Tunable Magnetometer Based on Superconducting Quantum Interference Device

Vettoliere

Granata

2023

Sensors

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In the present article, experimental results regarding fully integrated superconducting quantum interference devices (SQUID), including a circuit to tune and optimize the main sensor device characteristics, are reported. We show the possibility of modifying the critical current of a SQUID magnetometer in liquid helium by means of a suitable heating circuit. This allows us to improve the characteristics of the SQUID sensor and in particular to optimize the voltage–magnetic flux characteristic and the relative transfer factor (responsivity) and consequently to also improve the flux and magnetic field noise. It is also possible to reset the SQUID sensor in case of entrapment of magnetic flux, avoiding taking it out of the helium bath. These results are very useful in view of most SQUID applications such as those requiring large multichannel systems in which it is desirable to optimize and eventually reset the magnetic sensors in a simple and effective way.

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Superconducting quantum magnetic sensing

Cited by 11 publications

References 65 publications

Spin wave excitations in low dimensional systems with large magnetic anisotropy

Spin wave excitations in low dimensional systems with large magnetic anisotropy

Highly sensitive surface acoustic wave magnetic field sensor based on the loss mechanism

Highly Sensitive Tunable Magnetometer Based on Superconducting Quantum Interference Device

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