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Related papers: Spin-density fluctuations and the fluctuation-diss…

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Kagome antiferromagnetic metal FeSn has become an attracting platform for the exploration of novel electronic states, such as topological Dirac states and the formation of flat bands by localized electrons. Apart from the electronic…

Materials Science · Physics 2022-12-07 Yi-Fan Zhang , Xiao-Sheng Ni , Trinanjan Datta , Meng Wang , Dao-Xin Yao , Kun Cao

We theoretically study the spin susceptibility of Dirac semimetals using the linear response theory. The spin susceptibility is decomposed into an intraband contribution and an interband contribution. We obtain analytical expressions for…

Mesoscale and Nanoscale Physics · Physics 2018-06-22 Yuya Ominato , Kentaro Nomura

Thermal fluctuation of local magnetization in magnetic metals intercoupled with charge carriers and phonons offers a path to enhance thermoelectric performance. The thermopower enhancement by spin fluctuations (SF) has been observed before.…

Materials Science · Physics 2021-10-22 Md Mobarak Hossain Polash , Daryoosh Vashaee

Fluctuation dynamos provide a robust mechanism for amplifying weak seed magnetic fields in turbulent astrophysical plasmas. However, their behaviour in the highly compressible regimes characteristic of the interstellar medium remains…

Astrophysics of Galaxies · Physics 2026-02-18 Ameya Uday Nagdeo , Sharanya Sur , Bhargav Vaidya

Spin excitations play a fundamental role in understanding magnetic properties of materials, and have significant technological implications for magnonic devices. However, accurately modeling these in transition-metal and rare-earth…

Materials Science · Physics 2025-05-07 Luca Binci , Nicola Marzari , Iurii Timrov

Spins transverse to the magnetization of a ferromagnet only survives over a short distance. We develop a drift-diffusion approach that captures the main features of transverse spin effects in systems with arbitrary spin textures (vortices,…

Mesoscale and Nanoscale Physics · Physics 2013-07-29 Cyril Petitjean , David Luc , Xavier Waintal

We investigate theoretically the Seebeck effect in materials close to a ferromagnetic quantum critical point to explain anomalous behaviour at low temperatures. It is found that the main effect of spin fluctuations is to enhance the…

Strongly Correlated Electrons · Physics 2015-05-13 Takuya Okabe

We revisit the problem of diffusive proximity systems involving superconductors and normal metals (or ferromagnets) with magnetic disorder. On the length scales much larger than its correlation length, the effect of sufficiently weak…

Superconductivity · Physics 2009-10-05 D. A. Ivanov , Ya. V. Fominov , M. A. Skvortsov , P. M. Ostrovsky

We analyze the ground state energy and spin of quantum dots obtained from spin density functional theory (SDFT) calculations. First, we introduce a Strutinsky-type approximation, in which quantum interference is treated as a correction to a…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Denis Ullmo , Hong Jiang , Weitao Yang , Harold U. Baranger

We study magnetic fluctuations in a system of interacting spins on a lattice at high temperatures and in the presence of a spatially varying magnetic field. Starting from a microscopic Hamiltonian we derive effective equations of motion for…

Statistical Mechanics · Physics 2013-03-28 Andrew Sykes , Dmitry Solenov , Dmitry Mozyrsky

At the heart of current information nanotechnology lies the search for ideal platforms hosting the smallest possible magnets, i.e. single atoms with magnetic moments pointing out-of-plane, as requested in a binary-type of memory. For this…

We study dynamical spin structure factor (DSSF) of S = 1/2 Heisenberg model on the kagome lattice (KAFM) by means of density-matrix renormalization group. By comparison with the well-defined magnetic ordered state and chiral spin liquid…

Strongly Correlated Electrons · Physics 2019-05-22 W. Zhu , Shou-Shu Gong , D. N. Sheng

Little is known about the spin-flip diffusion length $l_{\rm sf}$, one of the most important material parameters in the field of spintronics. We use a density-functional-theory based scattering approach to determine values of $l_{\rm sf}$…

Mesoscale and Nanoscale Physics · Physics 2021-05-13 Rohit S. Nair , Ehsan Barati , Kriti Gupta , Zhe Yuan , Paul J. Kelly

We propose an alternative micromagnetic approach to determine the spin wave dispersion relations in magnonic structures. Characteristic of the method is that a limited area of the system is continuously excited with a spatially uniform…

Mesoscale and Nanoscale Physics · Physics 2014-03-12 Ben Van de Wiele , Federico Montoncello

We address the role of correlations between spin and charge degrees of freedom on the dynamical properties of ferromagnetic systems governed by the magnetic exchange interaction between itinerant and localized spins. For this we introduce a…

Strongly Correlated Electrons · Physics 2008-08-25 M. D. Kapetanakis , I. E. Perakis

We present a theoretical investigation of epitaxial strain effects on the magnetic fluctuation properties of Mn$_3$Sn noncollinear antiferromagnets. Employing density functional theory (DFT), we uncover significant strain-induced…

Materials Science · Physics 2025-07-31 Mohammad M. Rahman , Farzad Mahfouzi , Matthew W. Daniels , Mark D. Stiles

The density fluctuations of nuclear matter are studied within a mean-field model in wich fluctuations are generated by an external stochastic field. The constraints imposed on the random force by the fluctuation-dissipation theorem are…

Nuclear Theory · Physics 2009-11-06 F. Matera , A. Dellafiore

We develop a theory of thermal fluctuations of spin density emerging in a two-dimensional electron gas. The spin fluctuations probed at spatially separated spots of the sample are correlated due to Brownian motion of electrons and spin-obit…

Mesoscale and Nanoscale Physics · Physics 2015-08-05 A. V. Poshakinskiy , S. A. Tarasenko

In a stochastic process, where noise is always present, the fluctuation-dissipation theorem (FDT) becomes one of the most important tools in statistical mechanics and, consequently, it appears everywhere. Its major utility is to provide a…

Statistical Mechanics · Physics 2021-03-08 Márcio S. Gomes-Filho , Fernando A. Oliveira

Spin-transfer torque (STT) provides key mechanisms for current-induced phenomena in ferromagnets. While it is widely accepted that STT involves both adiabatic and non-adiabatic contributions, their underlying physics and range of validity…

Mesoscale and Nanoscale Physics · Physics 2013-07-23 Ran Cheng , Qian Niu