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Within massive gravity, we construct a gravity dual for insulator/metal phase transition and colossal magnetoresistance (CMR) effect found in some manganese oxides materials. In heavy graviton limit, a remarkable magnetic-field-sensitive DC…

高能物理 - 理论 · 物理学 2015-11-11 Rong-Gen Cai , Run-Qiu Yang

We report on a novel class of nanocrystalline/amorphous Gd$_3$Ni/Gd$_{65}$Ni$_{35}$ composite microwires, which was created directly by melt-extraction through controlled solidification. X-ray diffraction (XRD) and transmission electron…

It is now well established, both theoretically and experimentally, that very small changes in the size of isolated nanograins lead to substantial nonmonotonic variations, and sometimes enhancement, of the mean-field spectroscopic gap of…

超导电性 · 物理学 2014-11-04 James Mayoh , Antonio M. García-García

The magnetic state of Nitrogen-doped MgO, with N substituting O at concentrations between 1% and the concentrated limit, is calculated with density-functional methods. The N atoms are found to be magnetic with a moment of 1 Bohr magneton…

材料科学 · 物理学 2009-11-13 Phivos Mavropoulos , Marjana Lezaic , Stefan Blügel

We present a spin-rotation-invariant Green-function theory of long- and short-range order in the ferro- and antiferromagnetic Heisenberg model with arbitrary spin quantum number S on a stacked square lattice. The thermodynamic quantities…

强关联电子 · 物理学 2010-09-23 I. Juhász Junger , D. Ihle , J. Richter

We present a data set of calculated Curie temperatures for the main-phase compounds of rare-earth permanent magnets. We employ ab initio electronic structure calculations for the itinerant ferromagnetism and an effective spin model for the…

材料科学 · 物理学 2020-04-28 Munehisa Matsumoto , Hisazumi Akai

The pressure dependence of the Curie temperature $T_C$ in manganites, recently studied over a wide pressure range, is not quantitatively accounted for by the quenching of Jahn-Teller distortions, and suggests the occurrence of a new…

强关联电子 · 物理学 2007-09-19 A. Sacchetti , P. Postorino , M. Capone

We prepared very high-coercivity cobalt ferrite nanoparticles using short-time high-energy mechanical milling. After the milling process, the coercivity of the nanoparticles reached 3.75 kOe - a value almost five times higher than that…

介观与纳米尺度物理 · 物理学 2015-06-19 E. F. Chagas , A. S. Ponce , R. J. Prado , G. M. Silva , J. Bettini , E. Baggio-Saitovitch

In transition metal oxides, quantum confinement arising from a large surface to volume ratio often gives rise to novel physico-chemical properties at nanoscale. Their size dependent properties have potential applications in diverse areas,…

We investigate the contributions of finite-temperature magnetic fluctuations to the thermodynamic properties of bcc Fe as a function of pressure. First, we apply a tight-binding total-energy model parameterized to first-principles…

材料科学 · 物理学 2010-07-21 Xianwei Sha* , R. E. Cohen

Stefan-Boltzmann's law indicates that far-field blackbody radiation scales at the fourth power of temperature. The temperature dependence of radiative heat transfer in the near field is expected to be very different due to the contribution…

经典物理 · 物理学 2021-11-16 Christophe Lucchesi , Rodolphe Vaillon , Pierre-Olivier Chapuis

Nanoscale layered ferromagnets have demonstrated fascinating two-dimensional magnetism down to atomic layers, providing a peculiar playground of spin orders for investigating fundamental physics and spintronic applications. However,…

We report the observation of a quantum anomalous Hall effect in twisted bilayer graphene showing Hall resistance quantized to within .1\% of the von Klitzing constant $h/e^2$ at zero magnetic field.The effect is driven by intrinsic strong…

强关联电子 · 物理学 2020-03-18 M. Serlin , C. L. Tschirhart , H. Polshyn , Y. Zhang , J. Zhu , K. Watanabe , T. Taniguchi , L. Balents , A. F. Young

A quasi one-dimensional compound, Ca3CuRuO6, has been synthesized by solid-state reaction method and studied using magnetization (M) and heat capacity (C) measurements. This compound undergoes magnetic ordering (T_o) around 40 K, as…

强关联电子 · 物理学 2016-08-31 S. Rayaprol , E. V. Sampathkumaran

The magnetic properties of carbon nanotube encapsulated nickel nanowires (C.E. nanowires of diameter ~ 10 nm), and its comparison to other forms of Ni are carried out in this work. The saturation magnetization (M_s) and coercivity (H_c) for…

介观与纳米尺度物理 · 物理学 2010-09-21 Paramita Kar Choudhury , S. Banerjee , S. Ramaprabhu , K. P. Ramesh , Reghu Menon

The magnetocaloric properties of three samples of LaFe$_{13-x-y}$Co$_x$Si$_y$ have been measured and compared to measurements of commercial grade Gd. The samples have (x=0.86, y=1.08), (x=0.94, y=1.01) and (x=0.97, y=1.07) yielding Curie…

材料科学 · 物理学 2014-10-09 R. Bjørk , C. R. H. Bahl , M. Katter

The magnetic properties of alkali-metal peroxychromate K$_2$NaCrO$_8$ are governed by the $S = 1/2$ pentavalent chromium cation, Cr$^{5+}$. Specific heat, magnetocalorimetry, ac magnetic susceptibility, torque magnetometry, and inelastic…

A temperature dependent coherent magnetization reversal model is proposed for size-distributed assemblies of ferromagnetic nanoparticles and ferromagnetic-antiferromagnetic core-shell nanoparticles. The nanoparticles are assumed to be of…

Domain walls in nano-constrictions are investigated with a focus on thermal properties. In general, the magnetization component perpendicular to the easy axis which in a domain wall usually occurs has a value different from the easy-axis…

材料科学 · 物理学 2009-11-11 N. Kazantseva , R. Wieser , U. Nowak

We theoretically investigate impurity correlation and magnetic clustering effects on the long-range ferromagnetic ordering in diluted magnetic semiconductors, such as $\textrm{Ga}_{1-x}\textrm{Mn}_{x}\textrm{As}$, using analytical arguments…

材料科学 · 物理学 2009-11-11 D. J. Priour , S. Das Sarma
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