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A magnetic nanoparticle in a vortex state is a promising candidate for the information storage. One bit of information corresponds to the upward or downward magnetization of the vortex core (vortex polarity). Generic properties of the…

Strongly Correlated Electrons · Physics 2009-11-13 Yuri B. Gaididei , Volodymyr P. Kravchuk , Franz G. Mertens , Denis D. Sheka

Energy-efficient switching of nanoscale magnets requires the application of a time-varying magnetic field characterized by microwave frequency. At finite temperatures, even weak thermal fluctuations create perturbations in the magnetization…

Mesoscale and Nanoscale Physics · Physics 2023-12-19 Mohammad H. A. Badarneh , Grzegorz J. Kwiatkowski , Pavel F. Bessarab

The topological nature of magnetic-vortex state gives rise to peculiar magnetization reversal observed in magnetic microdisks. Interestingly, magnetostatic and exchange energies which drive this reversal can be effectively controlled in…

Other Condensed Matter · Physics 2017-09-13 Pavel N. Lapa , Junjia Ding , Charudatta Phatak , John E. Pearson , J. S. Jiang , Axel Hoffmann , Valentine Novosad

Fast magnetic fluctuations due to thermal torques have useful technological functionality ranging from cryptography to probabilistic computing. The characteristic time of fluctuations in typical uniaxial anisotropy magnets studied so far is…

Mesoscale and Nanoscale Physics · Physics 2019-12-04 Jan Kaiser , Avinash Rustagi , Kerem Y. Camsari , Jonathan Z. Sun , Supriyo Datta , Pramey Upadhyaya

Characteristic results of magnetism in small particles and thin films are presented. As a consequence of the reduced atomic coordination in small clusters and thin films the electronic states and density of states modify. Thus magnetic…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 K. H. Bennemann

Transport and non-equilibrium magnetization in monolayers of magnetic molecules subject to a bias voltage are considered. We apply a master-equation approach going beyond the sequential-tunneling approximation to study the Coulomb-blockade…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Florian Elste , Carsten Timm

Magnetic junction is considered which consists of two ferromagnetic metal layers, a thin nonmagnetic spacer in between, and nonmagnetic lead. Theory is developed of a magnetization reversal due to spin injection in the junction.…

Materials Science · Physics 2009-11-10 R. J. Elliott , E. M. Epshtein , Yu. V. Gulyaev , P. E. Zilberman

Measurements of the magnetic irreversibility line and time-logarithmic decay of the magnetization are described for three $Fe_{2}O_{3}$ samples composed of regular amorphous, acicular amorphous and crystalline nanoparticles. The relaxation…

Condensed Matter · Physics 2009-10-31 R. Prozorov , Y. Yeshurun , T. Prozorov , A. Gedanken

We argue that for some species of magnetic nanoparticles the macrospin can have a nonvanishing moment of inertia and then an orbital angular momentum. We represent such nanoparticles by two interacting rigid rotors one of which has a large…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 Keisuke Hatada , Kuniko Hayakawa , Augusto Marcelli , Fabrizio Palumbo

Below 360 mK, Fe magnetic molecular clusters are in the pure quantum relaxation regime and we show that the predicted square-root time relaxation is obeyed, allowing us to develop a new method for watching the evolution of the distribution…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 W. Wernsdorfer , T. Ohm , C. Sangregorio , R. Sessoli , D. Mailly , C. Paulsen

A new strategy is proposed aimed at substantially reducing the minimal magnetization switching field for a Stoner particle. Unlike the normal method of applying a static magnetic field which must be larger than the magnetic anisotropy, a…

Materials Science · Physics 2009-11-11 Z. Z. Sun , X. R. Wang

Magnetization measurements of a truly axial symmetry Mn12-tBuAc molecular nanomagnet with a spin ground state of S = 10 show resonance tunneling. This compound has the same magnetic anisotropy as Mn12-Ac but the molecules are better…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 W. Wernsdorfer , M. Murugesu , G. Christou

We theoretically study the transport properties of a supramolecular spin valve, consisting of a carbon nanotube with two attached magnetic molecules, weakly coupled to metallic contacts. The emphasis is put on analyzing the change of the…

Mesoscale and Nanoscale Physics · Physics 2019-03-19 A. Plominska , I. Weymann

We present a numerical study on the thermal activated avalanche dynamics in granular materials composed of ferromagnetic clusters embedded in a non-magnetic matrix. A microscopic dynamical simulation based on the reaction-diffusion process…

Disordered Systems and Neural Networks · Physics 2016-11-30 Gia-Wei Chern

Macroscopic quantum coherence oscillations in mesoscopic antiferromagnets may appear when the anisotropy potential creates a barrier between the antiferromagnetic states with opposite orientations of the Neel vector. This phenomenon is…

Quantum Physics · Physics 2011-08-04 Marius Grigorescu , Mahi R. Singh

The tunnel splitting in biaxial antiferromagnetic particles is studied with a magnetic field applied along the hard anisotropy axis. We observe the oscillation of tunnel splitting as a function of the magnetic field due to the quantum phase…

Condensed Matter · Physics 2019-08-17 Yi-Hang Nie , Yan-Hong Jin , J. -Q. Liang , H. J. W. Müller-Kirsten , D. K. Park , F. -C. Pu

We have studied the magnetization reversal process in FM/AFM bilayer structures through of spin dynamics simulation. It has been observed that the magnetization behavior is different at each branch of the hysteresis loop as well as the…

Materials Science · Physics 2014-03-24 E. B. Santos , P. Z. Coura , R. A. Dias , S. A. Leonel , J. C. S. Rocha

We report on our theoretical study of the inverse TMR effect in the spin polarized transport through a narrow channel. In the weak tunneling limit, we find the ordinary positive TMR. The TMR changes its sign as the transmission probability…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Tae-Suk Kim

We analyze the micromagnetics of short longitudinal modulations of a high-magnetization material in cylindrical nanowires made of a soft-magnetic material of lower magnetization such as permalloy, combining magnetic microscopy, analytical…

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