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We investigate persistent charge and spin currents in a magnetic quantum ring threaded by an Aharonov-Bohm flux, in the presence of a side-coupled one-dimensional non-magnetic chain. The neighboring magnetic moments in the ring are arranged…

Mesoscale and Nanoscale Physics · Physics 2025-07-25 Sourav Karmakar , Suparna Sarkar , Santanu K. Maiti

We calculate the average persistent current in a normal conducting, mesoscopic ring in the diffusive regime. In the presence of magnetic impurities, a contribution to the persistent current is identified, which is related to fluctuations in…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 P. Schwab , U. Eckern

We propose four different mechanisms responsible for paramagnetic or diamagnetic persistent currents in normal metal rings and determine the circumstances for change of the current from paramagnetic to diamagnetic ones and {\it vice versa}.…

Mesoscale and Nanoscale Physics · Physics 2010-10-19 Lukasz Machura , Szymon Rogozinski , Jerzy Luczka

We developed a method to calculate the magnetoresistance of magnetic nanostructures. We discretize a magnetic disk in small cells and numerically solve the Landau-Lifshitz-Gilbert (LLG) equation in order to obtain its magnetization profile.…

Mesoscale and Nanoscale Physics · Physics 2011-12-08 Tiago S. Machado , M. Argollo de Menezes , Tatiana G. Rappoport , Luiz C. Sampaio

Instead of computing magneticallly induced (MI) current densities (CD) via the wave function and their quatum mechanical definition one can also use the differential form of the Amp\`ere-Maxwell law to obtain them from spatial derivatives…

Chemical Physics · Physics 2025-01-13 Raphael J. F. Berger , Maria Dimitrova

Persistent current in one-dimensional non-superconducting mesoscopic rings threaded by a slowly varying magnetic flux $\phi$ is studied based on the tight-binding model. The behavior of the persistent current is discussed in three aspects:…

Mesoscale and Nanoscale Physics · Physics 2009-05-20 Santanu K. Maiti

We calculate magnetotransport oscillations in current through a triple-quantum-dot molecule, accounting for higher harmonics (having flux period h/ne, with n an integer). For a reflection-symmetric triple quantum dot, we find that harmonics…

Mesoscale and Nanoscale Physics · Physics 2013-02-28 B. D'Anjou , W. A. Coish

The equilibrium magnetic field inside axisymmetric plasmas with inversions on the toroidal current density is studied. Structurally stable non-nested magnetic surfaces are considered. For any inversion in the internal current density the…

Plasma Physics · Physics 2015-06-15 David Ciro , Iberê L. Caldas

A state where spin currents exist in the absence of external fields has recently been proposed to describe the superconducting state of metals. It is proposed here that such a state also describes the ground state of aromatic molecules. It…

Superconductivity · Physics 2010-08-10 J. E. Hirsch

Coherent resonant tunneling through an artificial molecule of quantum dots in an inhomogeneous magnetic field is investigated using an extended Hubbard model. Both the multiterminal conductance of an array of quantum dots and the persistent…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 C. A. Stafford , R. Kotlyar , S. Das Sarma

Persistent currents in disordered mesoscopic rings threaded by a magnetic flux are calculated using exact diagonalization methods in the one-dimensional (1D) case and self-consistent Hartree-Fock treatments for two dimensional (2D) systems.…

Condensed Matter · Physics 2008-02-03 Georges Bouzerar , Didier Poilblanc

We report the observation and micromagnetic analysis of current-driven magnetization switching in nanoscale ring-shaped magnetic tunnel junctions. When the electric current density exceeds a critical value of the order of $6\times…

Materials Science · Physics 2009-11-13 Hong-Xiang Wei , Jiexuan He , Zhen-Chao Wen , Xiu-Feng Han , Wen-Shan Zhan , Shufeng Zhang

We investigate the persistent currents and magnetization of a mesoscopic system consisting of two clean metallic rings sharing a single contact point in a magnetic field. Many novel features with respect to the single-ring geometry are…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Y. Avishai , J. M. Luck

The shape instability of magnetic domain walls under current is investigated in a ferromagnetic (Ga,Mn)(As,P) film with perpendicular anisotropy. Domain wall motion is driven by the spin transfer torque mechanism. A current density gradient…

The conductance resulting from resonant tunneling through a droplet of $N \sim 30$ electrons is used to measure its chemical potential $\mu_N$. Abrupt shifts of $\mu_N$ occur at sharply defined values of the magnetic field, at which the…

Condensed Matter · Physics 2007-05-23 O. Klein , C. de C. Chamon , D. Tang , D. M. Abusch-Magder , X. -G. Wen , M. A. Kastner , S. J. Wind

We investigate the current-excited magnetization dynamics in a narrow ferromagnetic Permalloy wire by means of Lorentz microscopy, together with the results of simultaneous transport measurements. A detailed structural evolution of the…

Using molecular dynamics simulations, we study particle-transport in a system of interacting colloidal particles on a ring, where the system is driven by a time-dependent external potential, moving along the ring. We consider two driving…

Statistical Mechanics · Physics 2018-12-06 Shubhashis Rana , Sanchari Goswami , Sakuntala Chatterjee , Punyabrata Pradhan

We present a numerical study of persistent currents in quantum rings using current spin density functional theory (CSDFT). This formalism allows for a systematic study of the joint effects of both spin, interactions and impurities for…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 S. Viefers , P. Singha Deo , S. M. Reimann , M. Manninen , M. Koskinen

The persistent current and charge stiffness of a one-dimensional Luttinger liquid on a ring threaded by a magnetic flux are calculated by Monte Carlo simulation. By changing the random impurity potential strength and the electron-electron…

Condensed Matter · Physics 2009-10-22 Hiroyuki Mori

In this work, we present ab initio cavity QED methods which include interactions with a static magnetic field and nuclear spin degrees of freedom using different treatments of the quantum electromagnetic field. We derive explicit…

Chemical Physics · Physics 2024-02-19 Alberto Barlini , Andrea Bianchi , Enrico Ronca , Henrik Koch