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The effect of magnetic anisotropy-axis alignment on the superparamagnetic (SPM) and superspin glass (SSG) states in a frozen ferrofluid has been investigated. The ferrofluid studied here consists of maghemite nanoparticles (\gamma-Fe2O3,…

The effect of magnetic anisotropy-axis alignment of individual nanoparticles on the collective aging behavior in the superspin glass state of a frozen ferrofluid has been investigated. The ferrofluid studied here consists of maghemite…

We present a microscopic model for nanoparticles, of the maghemite ($\gamma $% -Fe$_{2}$O$_{3}$) type, and perform classical Monte Carlo simulations of their magnetic properties. On account of M\"{o}ssbauer spectroscopy and high-field…

Materials Science · Physics 2009-10-31 H. Kachkachi , A. Ezzir , M. Nogues , E. Tronc

By combining first-principles electronic-structure calculations with the model Hamiltonian approach, we systematically study the magnetic properties of sodium superoxide (NaO2), originating from interacting superoxide molecules. We show…

Materials Science · Physics 2013-12-19 I. V. Solovyev , Z. V. Pchelkina , V. V. Mazurenko

A magnetite (Fe3O4) single crystal (111) surface has been studied at various oxygen-iron surface stoichiometries. The stoichiometry was modified by controlling the in-situ sample anneal conditions. We have found the conditions that lead to…

Soft Condensed Matter · Physics 2007-05-23 N. Berdunov , S. Murphy , G. Mariotto , I. V. Shvets

We have investigated the effect of nanometric grain size on magnetic properties of single phase, nanocrystalline, granular La0.7Ca0.3MnO3 (LCMO) sample. We have considered core-shell structure of our LCMO nanoparticles, which can explain…

Materials Science · Physics 2009-11-13 P. Dey , T. K. Nath , P. K. Manna , S. M. Yusuf

The oxidation of magnetite to maghemite is a naturally occurring process that leads to the degradation of the magnetic properties of magnetite nanoparticles. Despite being systematically observed with traditional macroscopic magnetization…

We report about the magnetic properties of antiferromagnetic (AF) MnO nanoparticles (NPs) with different sizes (6-19nm). Using a combination of polarized neutron scattering and magnetometry we were able to resolve previously observed…

Mesoscale and Nanoscale Physics · Physics 2017-04-26 X. Sun , A. Klapper , Y. Su , K. Nemkovski , A. Wildes , H. Bauer , O. Köhler , A. Schilmann , W. Tremel , O. Petracic , Th. Brückel

Disorder among surface spins largely dominates the magnetic response of ultrafine magnetic particle systems. In this work, we examine time-dependent magnetization in high-quality, monodisperse hollow maghemite nanoparticles with a 14.8…

Presence of Oxygen (O2) has been found by Energy Dispersive X-ray Analysis (EDAX) on the surfaces of flux grown BaFe2As2 single crystals which were kept in air ambience for several months. Transport studies show that the O2 adsorbed…

Superconductivity · Physics 2015-02-20 Nilotpal Ghosh , Santhosh Raj

Dynamic magnetic properties of $\mathrm{Y_{0.7}Ca_{0.3}MnO_{3}}$ are reported. The system appears to attain local ferromagnetic order at $T_{\mathrm{SRF}} \approx 70$ K. Below this temperature the low field magnetization becomes history…

Materials Science · Physics 2009-10-31 R. Mathieu , P. Nordblad , D. N. H. Nam , N. X. Phuc , N. V. Khiem

Magnetic properties of core-shell cobalt ferrite nanoparticles 15 to 48nm prepared by a sol-gel route have been studied. It is shown that the coercivity follows non-monotonic size dependence varying as 1/d above the maximum (d is the…

Pattern Formation and Solitons · Physics 2015-06-26 A. Mumtaz , K. Maaz , B. Janjua , S. K. Hasanain

A detailed analysis of damping and noise due to a {\it sd}-interaction in a thin ferromagnetic film sandwiched between two large normal metal layers is carried out. The magnetization is shown to obey in general a non-local equation of…

Materials Science · Physics 2009-11-10 A. Rebei , M. Simionato

A series of Ni0.6-x/2Zn0.4-x/2SnxFe2O4 (x = 0.0, 0.05, 0.1, 0.15, 0.2 and 0.3) (NZSFO) ferrite composites have been synthesized from nano powders using standard solid state reaction technique. The spinel cubic structure of the investigated…

Materials Science · Physics 2017-08-02 M. A. Ali , M. M. Uddin , M. N. I. Khan , F. -U. -Z. Chowdhury , S. M. Hoque , S. I. Liba

In the search for improved permanent magnets, fueled by the geostrategic and environmental issues associated with rare-earth-based magnets, magnetically hard (high anisotropy)-soft (high magnetization) composite magnets hold promise as…

Combined measurements of normal and inverted Hanle effects in CoFe/MgO/semiconductor (SC) contacts reveal the effect of spin relaxation rate on the interfacial spin depolarization (ISD) from local magnetic fields. Despite the similar…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Kun-Rok Jeon , Byoung-Chul Min , Youn-Ho Park , Young-Hun Jo , Seung-Young Park , Chang-Yup Park , Sung-Chul Shin

We have studied the magnetic behavior of dextran-coated magnetite (Fe$_3$O$_4$) nanoparticles with median particle size $\left<d\right>=8$ $nm$. Magnetization curves and in-field M\"ossbauer spectroscopy measurements showed that the…

Materials Science · Physics 2007-05-23 E. Lima , A. L. Brandl , A. D. Arelaro , G. F. Goya

We report muon-spin relaxation measurements on SrFeAsF, which is the parent compound of a newly discovered iron-arsenic-fluoride based series of superconducting materials. We find that this material has very similar magnetic properties to…

Superconductivity · Physics 2009-11-13 P. J. Baker , I. Franke , T. Lancaster , S. J. Blundell , L. Kerslake , S. J. Clarke

We investigated magnetization, muon spin rotation ($\mu$SR), and $^{119}Sn$ M\"{o}ssbauer spectroscopy on Sn substituted $CuCr_{2-x}Sn_xS_4$ (x=0.03 and 0.08) spinel compounds. The magnetization and $\mu$SR results reveal similar additional…

We present a simple, scalable synthesis route for producing exchange coupled soft/hard magnetic composite powder that outperforms pure soft and hard phase constituents. Importantly, the composites is iron oxide based (SrFe12O19 and Fe3O4)…

Materials Science · Physics 2016-07-20 A. D. Volodchenkov , Y. Kodera , J. E. Garay
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