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We develop a theory of spin noise spectroscopy of itinerant, noninteracting, spin-carrying fermions in different regimes of temperature and disorder. We use kinetic equations for the density matrix in spin variables. We find a general…

Statistical Mechanics · Physics 2015-05-14 Simon Kos , Alexander V. Balatsky , Peter B. Littlewood , Darryl L. Smith

We investigate vortex configuration in antiferromagnetic thin discs. It is shown that the vortex acquires oscillatory dynamics with well-defined amplitude and frequency which may be controlled on demand by an alternating spin polarized…

Mesoscale and Nanoscale Physics · Physics 2018-12-19 R. L. Silva , R. C. Silva , R. J. C. Lopes , W. A. Moura-Melo , A. R. Pereira

We report high-resolution measurements of voltage (V) noise in the mixed state of micrometre-sized thin films of amorphous Nb0.7Ge0.3, which is a good representative of weak-pinning superconductors. There is a remarkable difference between…

Superconductivity · Physics 2007-05-23 D. Babic , T. Nussbaumer , C. Strunk , C. Schoenenberger , C. Suergers

Due to their compact size and exceptional sensitivity at room temperature, magnetoresistance (MR) sensors have garnered considerable interest in numerous fields, particularly in the detection of weak magnetic signals in biological systems.…

Applied Physics · Physics 2024-06-25 Jiahui Luo , Zhaojie Xu , Zhenhu Jin , Mixia Wang , Xinxia Cai , Jiamin Chen

Low-frequency 1/f voltage noise has been employed to probe stochastic charge dynamics in AlO$_{x}$-based non-volatile resistive memory devices exhibiting both resistive switching (RS) and magneto-resistive (MR) effects. A 1/f$^{\gamma}$…

Mesoscale and Nanoscale Physics · Physics 2021-10-19 Jhen-Yong Hong , Chun-Yen Chen , Dah-Chin Ling , Isidoro Martínez , César González-Ruano , Farkhad G. Aliev

Non-uniform current distributions of spin valves with disk shaped free layers are investigated. In the context of spin valves, the vortex state, which is the ground-state in many disk shaped magnetic bodies, allows for distinct parallel…

In planar structures, the vortex resonance frequency changes little as a function of an in-plane magnetic field as long as the vortex state persists. Altering the topography of the element leads to a vastly different dynamic response that…

Sensing via a mechanical frequency shift is a powerful measurement tool, and, therefore, understanding and mitigating frequency noise affecting mechanical resonators is imperative. Thermomechanical noise fundamentally limits mechanical…

Mesoscale and Nanoscale Physics · Physics 2026-03-09 Sofia C. Brown , Ravid Shaniv , Ruomu Zhang , Chris Reetz , Cindy A. Regal

Atomtronic quantum sensors based on trapped superfluids offer a promising platform for high-precision inertial measurements where the dynamics of quantized vortices can serve as sensitive probes of external forces. We analytically…

Quantum Gases · Physics 2026-05-12 A. Chaika , A. O. Oliinyk , I. V. Yatsuta , M. Edwards , N. P. Proukakis , T. Bland , A. I. Yakimenko

Magnonics is a rapidly developing subfield of spintronics, which deals with devices and circuits that utilize spin currents carried by magnons - quanta of spin waves. Magnon current, i.e. spin waves, can be used for information processing,…

Mesoscale and Nanoscale Physics · Physics 2019-03-18 S. Rumyantsev , M. Balinskiy , F. Kargar , A. Khitun , A. A. Balandin

We demonstrate a technique that enables ferromagnetic resonance (FMR) measurements of the normal modes for magnetic excitations in individual nanoscale ferromagnets, smaller in volume by a factor of 1000 than can be probed by other methods.…

Materials Science · Physics 2009-11-11 J. C. Sankey , P. M. Braganca , A. G. F. Garcia , I. N. Krivorotov , R. A. Buhrman , D. C. Ralph

At absolute zero temperature, thermal noise vanishes when a physical system is in its ground state, but quantum noise remains as a fundamental limit to the accuracy of experimental measurements. Such a limitation, however, can be mitigated…

Condensed Matter · Physics 2009-11-10 J. Zhao , A. V. Bragas , D. J. Lockwood , R. Merlin

The microscopic origin of $1/f$ magnetic flux noise in superconducting circuits has remained an open question for several decades despite extensive experimental and theoretical investigation. Recent progress in superconducting devices for…

Present protocols for obtaining the ultimate magnetic sensitivity of optically pumped magnetometers (OPMs) utilizing alkali-metal ensembles rely on uncorrelated atoms in stretched states. A new approach for calculating the spin projection…

Quantum Physics · Physics 2024-02-23 K. Mouloudakis , V. Koutrouli , I. K. Kominis , M. W. Mitchell , G. Vasilakis

The tuning of sensitivity and dynamic range in linear magnetic sensors is required in various applications. We demonstrate the control and design of the sensitivity in magnetic tunnel junction (MTJ) sensors with a vortex-type sensing layer.…

Applied Physics · Physics 2022-02-02 Motoki Endo , Muftah Al-Mahdawi , Mikihiko Oogane , Yasuo Ando

Direct observation of vortex states in an antiferromagnetic layer have been recently reported [Wu, et al, Nature Phys. 7, 303 (2011)]. In contrast to their analogues in ferromagnetic systems, namely in nanomagnets, the vortex core of…

Materials Science · Physics 2011-08-05 R. L. Silva , R. D. Pereira , A. R. Pereira , W. A. Moura-Melo , L. A. S. Mol , A. S. T. Pires

We observe magnetization dynamics induced by spin momentum transfer in the noise spectra of current perpendicular to the plane giant magnetoresistance spin valves. The dynamics are observable only for those combinations of current direction…

Materials Science · Physics 2009-11-10 M. Covington , M. AlHajDarwish , Y. Ding , N. J. Gokemeijer , M. A. Seigler

Spatially-resolved NMR is used to probe the magnetism in and around vortex cores of nearly optimally-doped Tl_2Ba_2CuO_{6+x} (Tc=85 K). The NMR relaxation rate 1/T_1 at Tl site provides a direct evidence that the AF spin correlation is…

Superconductivity · Physics 2009-11-10 K. Kakuyanagi , K. Kumagai , Y. Matsuda , M. Hasegawa

1/f noise is a critical figure of merit for the performance of transistors and circuits. For two-dimensional devices (2D-FETs), and especially for applications in the GHz range where short-channel FETs are required, velocity saturation (VS)…

A micromagnetic numerical study of the precessional motion of the vortex and antivortex states in soft ferromagnetic circular nanodots is presented using Landau-Lifshitz-Gilbert dynamics. For sufficiently small dot thickness and diameter,…

Materials Science · Physics 2012-03-28 Andreas Lyberatos , Stavros Komineas , Nikos Papanicolaou