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We study the relaxation characteristics in the two-dimensional ($l^{}_x \times l^{}_y$) array of magnetic nanoparticles (MNPs) as a function of aspect ratio $A^{}_r=l^{}_y/l^{}_x$, dipolar interaction strength $h^{}_d$ and anisotropy axis…

Materials Science · Physics 2021-06-29 Manish Anand

We report detailed studies on non-equilibrium magnetic behavior of antiferromagnetic Co_3O_4 nanoparticles. Temperature and field dependence of magnetization, wait time dependence of magnetic relaxation (aging), memory effects and…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Vijay Bisht , K. P. Rajeev

The mechanism of magnetization reversal in single-domain ferromagnetic particles is of interest in many applications, in most of which losses must be minimized. In cancer therapy by hyperthermia the opposite requirement prevails: the…

Other Condensed Matter · Physics 2009-11-13 P. F. de Chatel , I. Nandori , J. Hakl , S. Meszaros , K. Vad

We report a novel method of determining the average Neel relaxation time and its temperature dependence by calculating derivatives of the measured time dependence of temperature for a frozen ferrofluid exposed to an alternating magnetic…

Materials Science · Physics 2015-09-02 R. J. Tackett , J. Thakur , N. Mosher , E. Perkins-Harbin , R. E. Kumon , L. Wang , C. Rablau , P. P. Vaishnava

Magnetic nanoparticle based hyperthermia emerged as a potential tool for treating malignant tumours. The efficiency of the method relies on the knowledge of magnetic properties of the samples; in particular, knowledge of the frequency…

We calculate the nuclear relaxation rate of oxygen in the undoped quasi two-dimensional quantum Heisenberg antiferromagnet Sr_2CuO_2Cl_2 above the Neel temperature. The calculation is performed at two-loop order with the help of the…

Strongly Correlated Electrons · Physics 2009-10-30 Peter Kopietz , Sudip Chakravarty

The electron-nuclear hyperfine interaction shows up in a variety of phenomena including e.g. NMR studies of correlated states and spin decoherence effects in quantum dots. Here we focus on the hyperfine coupling and the NMR spin relaxation…

Mesoscale and Nanoscale Physics · Physics 2016-12-28 Zoltán Okvátovity , Ferenc Simon , Balázs Dóra

The van der Waals (vdW) layered multiferroics, which host simultaneous ferroelectric and magnetic orders, have attracted attention not only for their potentials to be utilized in nanoelectric devices and spintronics, but also offer…

In this work, a successful synthesis of magnetic cobalt ferrite (CoFe2O4) nanoparticles is presented. The synthesized CoFe2O4 nanoparticles have a spherical shape and highly monodisperse in the selected solvent. The effect of different…

Materials Science · Physics 2019-11-19 Z. Mahhouti , H. El Moussaoui , T. Mahfoud , M. Hamedoun , M. El Marssi , A. Lahmar , A. El Kenz , A. Benyoussef

We report structural, magnetic and dielectric properties of Co1.5Fe1.5O4 nanoparticles and their composites with non-magnetic NaNO3. The samples were derived from metal nitrates solution at different pH values. The chemical routed sample…

Materials Science · Physics 2012-03-15 R. N. Bhowmik , P. Lokeswara Rao , J. Udaya Bhanu

We report on isothermal magnetization, M\"ossbauer spectroscopy, and magnetostriction as well as temperature-dependent alternating-current (ac) susceptibility, specific heat, and thermal expansion of single crystalline and polycrstalline…

Strongly Correlated Electrons · Physics 2018-02-28 M. Fix , A. Jesche , S. G. Jantz , S. A. Bräuninger , H. -H. Klauss , R. S. Manna , I. M. Pietsch , H. A. Höppe , P. C. Canfield

A new mechanism for relaxing the nuclear magnetic moments, in which a pair of spin-polarized BCS quasiparticles is emitted or absorbed, and which dominates at low temperature, is identified in type-II d-wave superconductors in an external…

Superconductivity · Physics 2010-03-29 Robert E. Throckmorton , Oskar Vafek

We study magnetic relaxation dynamics, memory and aging effects in interacting polydisperse antiferromagnetic NiO nanoparticles by solving a master equation using a two-state model. We investigate the effects of interactions using dipolar,…

Mesoscale and Nanoscale Physics · Physics 2011-07-20 Sunil Kumar Mishra , V. Subrahmanyam

We have studied the magnetic and power absorption properties of three samples of CoFe2O4 nanoparticles with sizes from 5 to 12 nm prepared by thermal decomposition of Fe (acac)3 and Co(acac)2 at high temperatures. The blocking temperatures…

Materials Science · Physics 2011-03-22 T. E. Torres , A. G. Roca , M. P. Morales , A. Ibarra , C. Marquina , M. R. Ibarra , G. F. Goya

We report studies on temperature, field and time dependence of magnetization on cupric oxide nanoparticles of sizes 9 nm, 13 nm and 16 nm. The nanoparticles show unusual features in comparison to other antiferromagnetic nanoparticle…

Mesoscale and Nanoscale Physics · Physics 2009-07-27 Vijay Kumar Bisht , K. P. Rajeev , Sangam Banerjee

We report nanoscale inter-particle magnetic orderings in self-assemblies of Fe3O4 nanoparticles (NPs), and the emergence of inter-particle antiferromagnetic (AF) (super-antiferromagnetic) correlations near the coercive field at low…

The magnetic behaviour of nanoparticles of antiferromagnetic ferritin has been investigated by 57Fe Mossbauer absorption spectroscopy and magnetisation measurements, in the temperature range 2.5K-250K and with magnetic fields up to 7T.…

Materials Science · Physics 2007-05-23 C. Gilles , P. Bonville , K. K. W. Wong , S. Mann

Spinel Fe3O4 nanoparticles have been produced through ball milling in methyl-alcohol (CH3OH), aiming to obtain samples with similar average particle sizes <d> and different interparticle interactions. Three samples having Fe3O4/CH3(OH) mass…

Materials Science · Physics 2011-03-24 Gerardo F. Goya

The relation of the magnetically dead layer and structural defects in ultrafine interacting NiFe2O4 nanoparticles (<d> = 4 nm) have been investigated using transmission electron microscopy, X-ray diffraction, ^57Fe M\"ossbauer spectroscopy,…

We explore the dielectric relaxation properties of NiFe nanowires in a nanoporous silicon template. Dielectric data of the NiFe-silicon structure show a strong relaxation resonance near 30K. This system shows Arrhenius type of behavior in…

Other Condensed Matter · Physics 2007-05-23 R. Vasic , J. S. Brooks , E. Jobiliong , S. Aravamudhan , K. Luongo , S. Bhansali