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Nuclear quadrupole resonance measurements were performed on the heavy fermion superconductor Ce2PdIn8. Above the Kondo coherence temperature T_coh \simeq 30K, the spin-lattice relaxation rate 1/T_1 is temperature independent, whereas at…

超导电性 · 物理学 2012-09-14 H. Fukazawa , R. Nagashima , S. Shimatani , Y. Kohori , D. Kaczorowski

We investigate the low-field relaxation of nuclear hyperpolarization in undoped and highly doped silicon microparticles at room temperature following removal from high field. For nominally undoped particles, two relaxation time scales are…

介观与纳米尺度物理 · 物理学 2011-07-21 M. Lee , M. C. Cassidy , C. Ramanathan , C. M. Marcus

This research paper investigates new and first insights into the magnetic and magnetocaloric properties of one-dimensional (1D) cobalt ferrite CoFe2O4 (CFO) nanofibers elaborated by sol gel based electrospinning technique, particularly…

We investigate the antiferromagnetic insulating nature of Ca3FeRhO6 both experimentally and theoretically. Susceptibility measurements reveal a Neel temperature T_N = 20 K, and a magnetic moment of 5.3 muB/f. u., while Moessbauer…

强关联电子 · 物理学 2007-05-23 V. Eyert , U. Schwingenschloegl , R. Fresard , A. Maignan , C. Martin , N. Nguyen , C. Hackenberger , T. Kopp

We study the Neel temperature of quasi one-dimensional S=1/2 antiferromagnets containing non-magnetic impurities. We first consider the temperature dependence of the staggered susceptibility of finite chains with open boundary conditions,…

强关联电子 · 物理学 2009-11-07 Sebastian Eggert , Ian Affleck , Matthew D. P. Horton

The thermally activated magnetic relaxation in two-dimensional ensembles of dipolar interacting nanoparticles with large uniaxial perpendicular anisotropy is studied by a numerical method and within the mean-field approximation. The role…

凝聚态物理 · 物理学 2009-11-10 S. I. Denisov , T. V. Lyutyy , K. N. Trohidou

We show that antiferromagnetic susceptibility in ferritin increases with temperature between 4.2 K and 180 K (i. e. below the N\'{e}el temperature) when taken as the derivative of the magnetization at high fields ($30\times10^4$ Oe). This…

强关联电子 · 物理学 2009-11-13 N. J. O. Silva , A. Millan , F. Palacio , E. Kampert , U. Zeitler , H. Rakoto , V. S. Amaral

We have investigated magnetic, dielectric and magnetodielectric properties of La2CoMnO6 nanoparticles prepared by sol-gel method. Magnetization measurements revealed two distinct ferromagnetic transitions at 218 K and 135 K that can be…

材料科学 · 物理学 2015-06-03 J. Krishna Murthy , A. Venimadhav

We report spatially resolved nuclear magnetic resonance measurements on a high temperature superconductor that indicate the presence of correlated antiferromagnetic fluctuations in the vortex core. The nuclear spin-lattice relaxation rate,…

超导电性 · 物理学 2009-09-29 V. F. Mitrovi{ć} , E. E. Sigmund , W. P. Halperin , A. P. Reyes , P. Kuhns , W. G. Moulton

Soft x-ray resonant scattering has been used to examine the charge and magnetic interactions in the cycloidal antiferromagnetic compound \dyfeal. By tuning to the Dy $M_4$ and $M_5$ absorption edges and the Fe L(2) and L(3) absorption edges…

强关联电子 · 物理学 2007-05-23 T. A. W. Beale , S. B. Wilkins , P. D. Hatton , P. Abbamonte , S. Stanescu , J. A. Paixao

The relaxation time of weakly interacting classical spins is calculated by introducing the averages of the local dipolar field, obtained by thermodynamic perturbation theory, in a rigorous expression for the single-spin thermoactivation…

材料科学 · 物理学 2009-11-07 P. E. Jönsson , J. L. Garcia-Palacios

Antiferromagnetic materials hold promising prospects in novel types of spintronics applications. Assessing the stability of antiferromagnetic nanostructures against thermal excitations is a crucial aspect of designing devices with a high…

介观与纳米尺度物理 · 物理学 2019-08-28 Levente Rózsa , Severin Selzer , Tobias Birk , Unai Atxitia , Ulrich Nowak

Magnetic nanoparticles of gamma-Fe2O3 coated by organic molecules and suspended in liquid and solid matrices, as well as a non-diluted magnetic fluid have been studied by electron magnetic resonance (EMR) at 77-380 K. Slightly asymmetric…

材料科学 · 物理学 2009-11-11 N. Noginova , F. Chen , T. Weaver , E. P. Giannelis , A. B. Bourlinos , V. A. Atsarkin

ZnO nanoparticles with Wurtzite structure were prepared by chemical methods at low temperature in aqueous solution. Nanoparticles are in the range from about 10 to 30 nm. Ferromagnetic properties were observed from 2 K to room temperature…

介观与纳米尺度物理 · 物理学 2015-05-20 R. Escudero , R. Escamilla

In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 and ferrimagnetic oxide/ferromagnetic metal CoFe2O4/CoFe2 nanocomposites. The latter compound is a good system to study hard ferrimagnet/soft ferromagnet…

Discontinuous magnetic multilayers [CoFe/Al2O3] are studied by use of magnetometry, susceptometry and numeric simulations. Soft ferromagnetic Co80Fe20 nanoparticles are embedded in a diamagnetic insulating a-Al2O3 matrix and can be…

材料科学 · 物理学 2010-09-13 O. Petracic , X. Chen , S. Bedanta , W. Kleemann , S. Sahoo , S. Cardoso , P. P. Freitas

Relaxor behavior and lattice dynamics have been studied for a single crystal of K$_{1-x}$Li$_x$TaO$_3$ $(x=0.05)$, where a small amount of a Ca impurity ($\sim 15$~ppm) was incorporated. The dielectric measurements revealed Debye-like…

材料科学 · 物理学 2009-11-11 S. Wakimoto , G. A. Samara , R. K. Grubbs , E. L. Venturini , L. A. Boatner , G. Xu , G. Shirane , S. -H. Lee

In this paper we report magnetic relaxation data for antiferromagnetic alpha-Fe2O3 particles of 5 nm mean diameter in the temperature range 0.1 K to 25 K. The average spin value of these particles S=124 and the uniaxial anisotropy constant…

凝聚态物理 · 物理学 2009-11-07 E. del Barco , J. M. Hernandez , M. Duran , J. Tejada , R. D. Zysler , M. Vasquez Mansilla , D. Fiorani

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…

材料科学 · 物理学 2007-05-23 E. Lima , A. L. Brandl , A. D. Arelaro , G. F. Goya

We calculate the N\'eel temperature $T_N$ for two-dimensional isotropic dipolar Heisenberg antiferromagnets via linear spin-wave theory and a high temperature expansion, employing the method of Callen. The theoretical predictions for $T_N$…

凝聚态物理 · 物理学 2009-10-22 C. Pich , F. Schwabl