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Single crystal spinel CoFe$_2$O$_4$ exhibits the largest room-temperature saturation magnetostriction among non-rare-earth compounds and a high Curie temperature ($T_c \sim 780$ K), properties that are critical to a wide range of industrial…

In a combined experimental and theoretical effort, we demonstrate a novel type of dipolar system made of ultracold bosonic dipolar molecules with large magnetic dipole moments. Our dipolar molecules are formed in weakly bound Feshbach…

Single molecule magnets (SMMs) with single-ion anisotropies $\mathbf d$, comparable to exchange interactions J, between spins have recently been synthesized. In this paper, we provide theoretical insights into the magnetism of such systems.…

Strongly Correlated Electrons · Physics 2017-11-22 Sumit Haldar , Rajamani Raghunathan , Jean-Pascal Sutter , S. Ramasesha

Controlling the preferred direction of the magnetic moments is essential for the design of spintronic devices based on ultrathin films and heterostructures. As the film thickness or the temperature is increased, the easy anisotropy axis is…

Materials Science · Physics 2020-10-21 Balázs Nagyfalusi , László Udvardi , László Szunyogh , Levente Rózsa

By means of density functional theory (DFT) and the generalized gradient approximation (GGA) we present a structural, electronic and magnetic study of FePt, CoPt, FeAu and FePd based L1$_0$ ordered cuboctahedral nanoparticles, with total…

Materials Science · Physics 2015-06-05 R. Cuadrado , R. W. Chantrell

We present a finite-temperature theory of the anisotropic spin-spin correlations in magnetic metallic monolayers, deposited on a suitable substrate. The `spins' are the local moments set up by the itinerant electrons, and the key concept is…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 M. dos Santos Dias , J. B. Staunton , A. Deak , L. Szunyogh

For studying the interplay of dipolar interaction and anisotropy energy in systems of ultrafine magnetic particles we consider simple cubic systems of magnetic dipoles with anisotropy axes pointing into the $z$-direction. Using Monte Carlo…

Disordered Systems and Neural Networks · Physics 2009-11-11 Stefanie Russ , Armin Bunde

Detailed understanding of spin dynamics in magnetic nanomaterials is necessary for developing ultrafast, low-energy and high-density spintronic logic and memory. Here, we develop micromagnetic models and analytical solutions to elucidate…

Materials Science · Physics 2020-04-28 Furkan Şahbaz , Mehmet C. Onbaşlı

The interaction between spherical magnetic nanoparticles is investigated from micromagnetic simulations and ananlysed in terms of the leading dipolar interaction energy between magnetic dipoles. We focus mainly on the case where the…

Materials Science · Physics 2009-04-14 V. Russier

Magnetization measurements made in small fields as a function of temperature reveal an unusual equilibrium below 900 mK for the molecular nano-magnet Fe_8. Measurements of the relaxation of the magnetization demonstrate that the approach to…

Other Condensed Matter · Physics 2007-05-23 V. Villar , E. Lhotel , C. Sangregorio , C. Paulsen

We propose a scheme to realize a pseudospin-$1/2$ model of the $^{1}\Sigma(v=0)$ bialkali polar molecules with the spin states corresponding to two sublevels of the first excited rotational level. We show that the effective dipole-dipole…

Quantum Gases · Physics 2015-09-30 Y. Deng , S. Yi

8~nm epsilon-Fe2O3 nanoparticles exhibit a spin reorientation transition that begins at 150 K which is a hallmark of this unique iron-oxide polymorph. We find that the change from the high to low temperature magnetic structures has been…

Mesoscale and Nanoscale Physics · Physics 2019-10-02 Richard Jones , Rachel Nickel , Palash K. Manna , J. Hilman , Johan van Lierop

Applications based on aggregates of magnetic nanoparticles are becoming increasingly widespread, ranging from hyperthermia to magnetic recording. However, although some uses require a collective behavior, other need a more individual-like…

The synthesis, crystal structure and magnetic characterization of a high spin cluster comprising eight iron ions, are presented in this contribution. The cluster has formula [(tacn)6Fe8O2(OH)12Br4.3(ClO4)3.7]6H2O, (Fe8PCL) where tacn is the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. L. Barra , F. Bencini , A. Caneschi , D. Gatteschi , C. Paulsen , C. Sangregorio , R. Sessoli , L. Sorace

We report the results of a comparative study of the magnetic microstructure of textured and isotropic $\mathrm{Nd}_2\mathrm{Fe}_{14}\mathrm{B}/\alpha$-$\mathrm{Fe}$ nanocomposites using magnetometry, transmission electron microscopy,…

The magnetization curves of densely packed single domain magnetic nanoparticles (MNP) are investigated by Monte Carlo simulations in the framework of an effective one spin model. The particles whose size polydispersity is taken into account…

Materials Science · Physics 2014-03-21 V. Russier , C. de-Montferrand , Y. Lalatonne , L. Motte

We study low temperature resonant spin tunneling in molecular magnets induced by a field sweep with account of dipole-dipole interactions. Numerical simulations uncovered formation of self-organized patterns of the magnetization and of the…

Statistical Mechanics · Physics 2012-02-21 D. A. Garanin , E. M. Chudnovsky

Spin dynamics of assemblies of magnetic nanomolecules and nanoclusters can be made coherent by inserting the sample into a coil of a resonant electric circuit. Coherence is organized through the arising feedback magnetic field of the coil.…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 V. I. Yukalov , V. K. Henner , E. P. Yukalova

We combine the anisotropy of magnetic interactions and the point symmetry of finite solids in the study of dipolar clusters as new basic units for multiferroics metamaterials. The hamiltonian of magnetic dipoles with an easy axis at the…

Materials Science · Physics 2020-12-03 Paula Mellado , Andres Concha , Sergio Rica

At temperatures below the magnetic anisotropy energy, monodomain magnetic systems (small particles, nanomagnetic devices, etc.) must relax quantum mechanically. This quantum relaxation must be mediated by the coupling to both nuclear spins…

Condensed Matter · Physics 2009-10-28 N. V. Prokof'ev , P. C. E. Stamp
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