Search results for "magnetismi"
showing 10 items of 30 documents
Generalized finite difference schemes with higher order Whitney forms
2021
Finite difference kind of schemes are popular in approximating wave propagation problems in finite dimensional spaces. While Yee’s original paper on the finite difference method is already from the sixties, mathematically there still remains questions which are not yet satisfactorily covered. In this paper, we address two issues of this kind. Firstly, in the literature Yee’s scheme is constructed separately for each particular type of wave problem. Here, we explicitly generalize the Yee scheme to a class of wave problems that covers at large physics field theories. For this we introduce Yee’s scheme for all problems of a class characterised on a Minkowski manifold by (i) a pair of first ord…
Observation of Poincaré-Andronov-Hopf Bifurcation in Cyclotron Maser Emission from a Magnetic Plasma Trap
2018
We report the first experimental evidence of a controlled transition from the generation of periodic bursts of electromagnetic radiation into the continuous-wave regime of a cyclotron maser formed in magnetically confined nonequilibrium plasma. The kinetic cyclotron instability of the extraordinary wave of weakly inhomogeneous magnetized plasma is driven by the anisotropic electron population resulting from electron cyclotron plasma heating in a MHD-stable minimum-B open magnetic trap. peerReviewed
θ0 thermal Josephson junction
2017
We predict the thermal counterpart of the anomalous Josephson effect in superconductor/ferromagnet/superconductor junctions with noncoplanar magnetic texture. The heat current through the junction is shown to have the phase-sensitive interference component proportional to cos(θ−θ0), where θ is the Josephson phase difference and θ0 is the texture-dependent phase shift. In the generic trilayer magnetic structure with the spin-filtering tunnel barrier θ0 is determined by the spin chirality of magnetic configuration and can be considered as the direct manifestation of the energy transport with participation of spin-triplet Cooper pairs. In case of the ideal spin filter the phase shift is shown …
Coexistence of long-range antiferromagnetic order and slow relaxation of the magnetization in the first lanthanide complex of a 1,2,4-benzotriazinyl …
2017
The first lanthanide complex of a 1,2,4-benzotriazinyl radical (1), Dy(1)(tbacac)3 (2, tbacac = 2,2,6,6-tetramethyl-3,5-heptane-dionato), was synthesised and found to have an antiferromagnetically ordered ground state with a metamagnetic phase diagram and a critical field of 0.91 T at 1.85 K. The application of a small dc field revealed the single-molecule magnet behaviour of 2, illustrating the coexistence of long-range antiferromagnetic order and slow relaxation of the magnetization. peerReviewed
Diamagnetic susceptibility from a nonadiabatic path-integral simulation of few-electron systems
2022
Diamagnetism is the response of dynamical compositions of charged particles, electrons, and nuclei, to an incident magnetic field. In this paper, we study how the finite temperature and finite nuclear masses affect the diamagnetic susceptibilities of selected small atoms and molecules, as limiting cases of dilute gas. We use nonrelativistic path-integral Monte Carlo simulation (PIMC), where both electrons and nuclei are treated on equal footing at finite temperatures in sampling exact Coulomb pair density matrices. The PIMC estimator of diamagnetic susceptibility has been briefly introduced in Ceperley [D. M. Ceperley, Rev. Mod. Phys. 67, 279 (1995)], but here we present a comprehensive der…
The M4 transitions of isomeric states
2015
Tässä pro gradu -tutkielmassa tutkitaan isomeeristen tilojen magneettisten M4-gammasiirtymien redusoituja matriisielementtejä. Tutkittavat siirtymät ovat venyneitä M4-siirtymiä kaksoisbeetahajoamisten massa-alueilla A=85-115 ja A=135-143. Tutkielman tarkoituksena on verrata kokeellisia ydinmatriisielementtejä kvasihiukkasmatriisielementteihin ja MQPM-teorian avulla laskettuihin matriisielementteihin. Kokeelliset matriisielementi lasketaan kokeellisesti määritettyjen arvojen avulla ja kvasihiukkas- sekä MQPM-matriisielementit määritetään tietokoneohjelmien avulla. Kokeellisten ja kvasihiukkasmatriisielementtien välinen suhde osoittautui olevan noin 0,29 ja kokeellisten ja MQPM-matriisielemen…
Spin and charge currents driven by the Higgs mode in high-field superconductors
2020
The Higgs mode in superconducting materials describes slowly decaying oscillations of the order parameter amplitude. We demonstrate that in superconductors with a built-in spin-splitting field the Higgs mode is strongly coupled to the spin degrees of freedom, allowing for the generation of time-dependent spin currents. Converting such spin currents to electric signals by spin-filtering elements provides a tool for the second-harmonic generation and the electrical detection of the Higgs mode generated by the external irradiation. The nonadiabatic spin torques generated by these spin currents allow for the magnetic detection of the Higgs mode by measuring the precession of the magnetic moment…
Code for manuscript: Nonreciprocal Josephson linear response
2023
Codes related to manuscript "Nonreciprocal Josephson linear response", including the scripts that generate the figures in the manuscript. The preprint is available at https://doi.org/10.48550/arXiv.2306.12295 This is a snapshot of the code dataset that has been taken on 06.07.2023. A more detailed description of the data and the address to the GitLab repository for the latest version of the code can be found from the parent dataset of this data publication.
Nonreciprocal Josephson linear response (parent repository)
2023
The repository contains computer codes related to manuscript "Nonreciprocal Josephson linear response", including the scripts that generate the figures in the manuscript. The preprint is available at https://doi.org/10.48550/arXiv.2306.12295 This is the metadata for the parent repository of the codes. Updates and possible corrections are documented in the GitLab project, where the material saved and shared. The GitLab project can be found and downloaded from the following address: https://gitlab.jyu.fi/jyucmt/2023-nonreciprocal-josephson
Plasman diamagnetismi ECR-ionilähteessä
2009
Tässä tutkielmassa pyritään esittämään teoreettiset lähtökohdat plasman diamagneettisen ilmiön kuvaamiselle magnetohydrodynamiikan avulla. Teoreettisessa osiossa määritellään mitä plasma on ja johdetaan plasmalle karakteristiset ominaisuudet. Koska plasma on pääasiassa ionisoitunutta kaasua, se käyttäytyy kuten neste, johon vaikuttavat sähköiset ja magneettiset voimat. Altistettaessa plasma ulkoiselle magneettikentälle, plasman sisällä syntyy diamagneettinen virta, joka synnyttää ulkoista magneettikenttää heikentävän kentän. Tätä ilmiötä kutsutaan plasman diamagneettiseksi ilmiöksi. Kokeellisessa osiossa esitetään ECR-ionilähteen tärkeimmät ominaisuudet, toimintaperiaate sekä lähtökohdat pl…