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The relaxation rate and temperature-dependent switching field curve of a spherical magnetic nanocluster are calculated by taking into account the effect of surface anisotropy via an effective anisotropy model. In particular, it is shown…

Materials Science · Physics 2009-11-13 P. -M. Dejardin , H. Kachkachi , Yu. P. Kalmykov

We study analytically the precessional switching of the magnetization of a thin macrospin. We analyze its response when subjected to an external field along its in-plane hard axis. We derive the exact trajectories of the magnetization. The…

Strongly Correlated Electrons · Physics 2009-11-10 T. Devolder , C. Chappert

We calculate the response of a molecular magnet subject to a time-varying magnetic field and coupled to a heat bath. We propose that observations of calculated oscillations transverse to the field direction may be an effective way of…

Statistical Mechanics · Physics 2007-05-23 Maxime Clusel , Timothy Ziman

We report on room temperature magnetoresistance and low frequency noise in sub-100nm elliptic CoFeB/MgO/CoFeB magnetic tunnel junctions with ultrathin (0.9nm) barriers. For magnetic fields applied along the hard axis, we observe current…

Mesoscale and Nanoscale Physics · Physics 2013-05-28 J. P. Cascales , D. Herranz , J. L. Sambricio , U. Ebels , J. A. Katine , F. G. Aliev

A superconducting quantum magnetometer based on magnetic flux-driven modulation of the density of states of a proximized metallic nanowire is theoretically analyzed. With optimized geometrical and material parameters transfer functions up…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 F. Giazotto , F. Taddei

We consider the interaction of a quantum mechanical SQUID ring with a classical resonator (a parallel $LC$ tank circuit). In our model we assume that the evolution of the ring maintains its quantum mechanical nature, even though the circuit…

Superconductivity · Physics 2007-05-23 M. J. Everitt , T. D. Clark , P. B. Stiffell , C. J. Harland , J. F. Ralph

We study the magnetization dynamics of thin-film magnetic elements with in-plane magnetization subject to a spin-current flowing perpendicular to the film plane. We derive a reduced partial differential equation for the in-plane…

Mesoscale and Nanoscale Physics · Physics 2016-10-26 Ross G. Lund , Gabriel D. Chaves O'Flynn , Andrew D. Kent , Cyrill B. Muratov

A quantum Heisenberg model with anisotropic coupling and all-to-all interaction has been analyzed using the Bose-Einstein statistics. In Ref.\cite{jsp} the existence of a classical energy disconnection border (EDB) in the same kind of…

Other Condensed Matter · Physics 2013-05-29 F. Borgonovi , G. L. Celardo , G. P. Berman

We investigate the magnetization reversal mechanism in an individual permalloy (Py) nanotube (NT) using a hybrid magnetometer consisting of a nanometer-scale SQUID (nanoSQUID) and a cantilever torque sensor. The Py NT is affixed to the tip…

We review the present state of theory and experiments on the quantum tunneling of magnetization in mesoscopic spin systems. Most attention is paid to the relaxation of magnetization in the molecular complexes Mn12 and Fe8. The role of the…

Condensed Matter · Physics 2007-05-23 Igor Tupitsyn , Bernard Barbara

Using a new microSQUID set-up, we investigate magnetic anisotropy in a single 1000-atoms cobalt cluster. This system opens new fields in the characterization and the understanding of the origin of magnetic anisotropy in such nanoparticles.…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 M. Jamet , W. Wernsdorfer , C. Thirion , D. Mailly , V. Dupuis , P. Melinon , A. Perez

The superconducting quantum interference device (SQUID) magnetometer is one of the most sensitive experimental techniques to magnetically characterize samples with high sensitivity. Here we present a detailed discussion of possible…

Materials Science · Physics 2015-05-27 M. Sawicki , W. Stefanowicz , A. Ney

We have calculated the momentum distributions of nanoparticles in diffraction and interference dependent on the effective screening mass parameter or size parameter and presented the calculations for a nanoparticle inside an infinite square…

General Physics · Physics 2007-05-23 Wang Guowen

Quantum mechanical objects or nanoobjects have been proposed as bits for information storage. While time-averaged properties of magnetic, quantum-mechanical particles have been extensively studied experimentally and theoretically,…

Quantum Physics · Physics 2016-04-20 M. Krizanac , D. Altwein , E. Y. Vedmedenko , R. Wiesendanger

Miniaturization of superconducting quantum interference devices (SQUIDs) is of major importance for the development of sensitive scanning nanoscale magnetometry tools. The high sensitivity of nanoSQUIDs is restricted, however, to only…

Superconductivity · Physics 2016-11-28 Alexander Y. Meltzer , Aviram Uri , Eli Zeldov

The pulse-noise approach to systems of classical spins weakly interacting with the bath has been applied to study thermally-activated escape of magnetic nanoparticles over the uniform and nonuniform energy barriers at intermediate and low…

Statistical Mechanics · Physics 2018-10-24 D. A. Garanin

This chapter takes a microscopic view of quantum tunneling of magnetization (QTM) in single-molecule magnets (SMMs), focusing on the interplay between exchange and anisotropy. Careful consideration is given to the relationship between…

Mesoscale and Nanoscale Physics · Physics 2013-03-04 Junjie Liu , Enrique del Barco , Stephen Hill

In recent years, studies on cyclic molecular nanomagnets have captivated the attention of researchers. These magnets are finite in size and contain very large spins. They are interesting because they possess macroscopic quantum tunneling of…

Mesoscale and Nanoscale Physics · Physics 2015-05-29 S. A. Owerre , J. Nsofini

We have performed magnetoresistance measurements on single-domain, submicron elliptical Ni particles using nonmagnetic probes in a four probe geometry at liquid helium temperatures. In the smallest particles, the magnetoresistance shows…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 J. Aumentado , V. Chandrasekhar

We investigate the thermal activated magnetisation reversal in a single ferromagnetic nanoparticle with uniaxial anisotropy using Monte Carlo simulations. The aim of this work is to reproduce the reversal magnetisation by uniform rotation…

Materials Science · Physics 2009-11-10 Denis Ledue , Pierre-Emmanuel Berche , Renaud Patte