Scan Science and Technology

Contact Leading Edge Experts & Companies

14,000,000 Leading Edge Experts on the ideXlab platform

14,000,000

Leading Edge Experts

on the ideXlab platform

Plateau

The Experts below are selected from a list of 281292 Experts worldwide ranked by ideXlab platform

Plateau - Free Register to Access Experts & Abstracts

Shin Miyahara - One of the best experts on this subject based on the ideXlab platform.

  • theory of the orthogonal dimer heisenberg spin model for srcu2 bo3 2
    Journal of Physics: Condensed Matter, 2003
    Co-Authors: Shin Miyahara, Kazuo Ueda
    Abstract:

    The magnetic properties of SrCu2 (BO3)2 are reviewed from a theoretical point of view. SrCu2 (BO3)2 is a new two-dimensional spin gap system and its magnetic properties are well described by a spin-1/2 antiferromagnetic Heisenberg model of the orthogonal dimer lattice. The model has a dimer singlet ground state whose exactness was proven by Shastry and Sutherland for a topologically equivalent model more than 20 years ago. The exactness of the ground state is maintained even if interlayer couplings are introduced for SrCu2 (BO3)2. In the two-dimensional model, quantum phase transitions take place between different ground states for which three phases are expected: a gapped dimer singlet state, a plaquette resonating valence bond state and a gapless magnetic ordered state. Analysis of the experimental data shows that the dimer singlet ground state is realized in SrCu2 (BO3)2. The orthogonality of the dimer bonds, which is the underlying symmetry of the exactness of the ground state, also leads to an unusual property of elementary excitations, namely the almost localized nature of the triplet excitations. Application of an external magnetic field changes the density of the triplet excitations. In general, there is competition between kinetic energies and interaction energies between triplets. The almost localized nature of the triplets makes it easy to form regular lattices. In fact, at certain densities, where the commensurability energy is significant, the triplet excitations form superstructures and Plateaux appear at 1/2, 1/3, 1/4 and 1/8 in the magnetization curve. In high-magnetic-field experiments, magnetic Plateaux at magnetizations of 1/3, 1/4 and 1/8 have been observed. Translational symmetry of the lattice is spontaneously broken at the Plateaux, except for the 1/2 Plateau. The 1/3 and 1/4 Plateaux are expected to have magnetic superstructures of stripe form while the 1/2 Plateau has a square unit cell and the 1/8 Plateau a rhomboid cell. Especially at the 1/8 Plateau, nuclear magnetic resonance experiments indicate the presence of at least 11 distinct Cu sites with different spin polarizations, which is the first evidence of breaking of the translational symmetry at the Plateau phase. The spin texture calculated on the basis of a Heisenberg model with adiabatic spin–phonon coupling is consistent with the experimental results.

B D Gaulin - One of the best experts on this subject based on the ideXlab platform.

  • magnetostriction and magnetic texture to 100 75 tesla in frustrated srcu2 bo3 2
    Proceedings of the National Academy of Sciences of the United States of America, 2012
    Co-Authors: M Jaime, Ramzy Daou, S A Crooker, Franziska Weickert, Atsuko Uchida, A E Feiguin, C D Batista, Hanna Dabkowska, B D Gaulin
    Abstract:

    Strong geometrical frustration in magnets leads to exotic states such as spin liquids, spin supersolids, and complex magnetic textures. SrCu2(BO3)2, a spin-1/2 Heisenberg antiferromagnet in the archetypical Shastry–Sutherland lattice, exhibits a rich spectrum of magnetization Plateaus and stripe-like magnetic textures in applied fields. The structure of these Plateaus is still highly controversial due to the intrinsic complexity associated with frustration and competing length scales. We discover magnetic textures in SrCu2(BO3)2 via magnetostriction and magnetocaloric measurements in fields up to 100.75 T. In addition to observing low-field fine structure with unprecedented resolution, the data also reveal lattice responses at 73.6 T and at 82 T that we attribute, using a controlled density matrix renormalization group approach, to a unanticipated 2/5 Plateau and to the long-predicted 1/2 Plateau.

Kazuo Ueda - One of the best experts on this subject based on the ideXlab platform.

  • theory of the orthogonal dimer heisenberg spin model for srcu2 bo3 2
    Journal of Physics: Condensed Matter, 2003
    Co-Authors: Shin Miyahara, Kazuo Ueda
    Abstract:

    The magnetic properties of SrCu2 (BO3)2 are reviewed from a theoretical point of view. SrCu2 (BO3)2 is a new two-dimensional spin gap system and its magnetic properties are well described by a spin-1/2 antiferromagnetic Heisenberg model of the orthogonal dimer lattice. The model has a dimer singlet ground state whose exactness was proven by Shastry and Sutherland for a topologically equivalent model more than 20 years ago. The exactness of the ground state is maintained even if interlayer couplings are introduced for SrCu2 (BO3)2. In the two-dimensional model, quantum phase transitions take place between different ground states for which three phases are expected: a gapped dimer singlet state, a plaquette resonating valence bond state and a gapless magnetic ordered state. Analysis of the experimental data shows that the dimer singlet ground state is realized in SrCu2 (BO3)2. The orthogonality of the dimer bonds, which is the underlying symmetry of the exactness of the ground state, also leads to an unusual property of elementary excitations, namely the almost localized nature of the triplet excitations. Application of an external magnetic field changes the density of the triplet excitations. In general, there is competition between kinetic energies and interaction energies between triplets. The almost localized nature of the triplets makes it easy to form regular lattices. In fact, at certain densities, where the commensurability energy is significant, the triplet excitations form superstructures and Plateaux appear at 1/2, 1/3, 1/4 and 1/8 in the magnetization curve. In high-magnetic-field experiments, magnetic Plateaux at magnetizations of 1/3, 1/4 and 1/8 have been observed. Translational symmetry of the lattice is spontaneously broken at the Plateaux, except for the 1/2 Plateau. The 1/3 and 1/4 Plateaux are expected to have magnetic superstructures of stripe form while the 1/2 Plateau has a square unit cell and the 1/8 Plateau a rhomboid cell. Especially at the 1/8 Plateau, nuclear magnetic resonance experiments indicate the presence of at least 11 distinct Cu sites with different spin polarizations, which is the first evidence of breaking of the translational symmetry at the Plateau phase. The spin texture calculated on the basis of a Heisenberg model with adiabatic spin–phonon coupling is consistent with the experimental results.

Frederic Mila - One of the best experts on this subject based on the ideXlab platform.

  • incomplete devil s staircase in the magnetization curve of srcu2 bo3 2
    Physical Review Letters, 2013
    Co-Authors: M Takigawa, M Horvatic, Takeshi Waki, S Kramer, C Berthier, Florence Levybertrand, I Sheikin, Hiroshi Kageyama, Yuytaka Ueda, Frederic Mila
    Abstract:

    We report on NMR and torque measurements on the frustrated quasi-two-dimensional spin-dimer system SrCu2(BO3)(2) in magnetic fields up to 34 T that reveal a sequence of magnetization Plateaus at 1/8, 2/15, 1/6, and 1/4 of the saturation and two incommensurate phases below and above the 1/6 Plateau. The magnetic structures determined by NMR involve a stripe order of triplets in all Plateaus, suggesting that the incommensurate phases originate from proliferation of domain walls. We propose that the magnetization process of SrCu2(BO3)(2) is best described as an incomplete devil's staircase. DOI: 10.1103/PhysRevLett.110.067210

P Vargas - One of the best experts on this subject based on the ideXlab platform.

  • metastable states in the triangular lattice ising model studied by monte carlo simulations application to the spin chain compoundca3co2o6
    Physical Review B, 2009
    Co-Authors: R Soto, G Martinez, M N Baibich, J M Florez, P Vargas
    Abstract:

    It is known that the spin-chain compound Ca3Co2O6 exhibits very interesting Plateaus in the magnetization as a function of the magnetic field at low temperatures. The origin of them is still controversial. In this paper we study the thermal behavior of this compound with a single-flip Monte Carlo simulation on a triangular lattice and demonstrate the decisive influence of metastable states in the splitting of the ferrimagnetic 1/3 Plateau below 10 K. We consider the [Co2O6]n chains as giant magnetic moments described by large Ising spins on planar clusters with open boundary conditions. With this simple frozen-moment model we obtain stepped magnetization curves which agree quite well with the experimental results for different sweeping rates. We describe particularly the out-of-equilibrium states that split the low-temperature 1/3 Plateau into three steps. They relax thermally to the 1/3 Plateau, which has long-range order at the equilibrium. Such states are further analyzed with snapshots unveiling a domain-wall structure that is responsible for the observed behavior of the 1/3 Plateau. A comparison is also given of the exact results in small triangular clusters with our Monte Carlo results, providing further support for our thermal description of this compound.