Topic
Spin-½
About: Spin-½ is a research topic. Over the lifetime, 40423 publications have been published within this topic receiving 796639 citations.
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TL;DR: In this article, the ground state properties of frustrated quantum Heisenberg antiferromagnet on the square lattice (J 1 - J 2 model) were investigated using exact diagonalization of finite clusters with 16, 20, 32, and 36 sites.
Abstract: We have performed a numerical investigation of the ground state properties of the frustrated quantum Heisenberg antiferromagnet on the square lattice (J 1 - J 2 model), using exact diagonalization of finite clusters with 16, 20, 32, and 36 sites. Using a finite-size scaling analysis we obtain results for a number of physical properties : magnetic order parameters, ground state energy, and magnetic susceptibility (at q = 0). In order to assess the reliability of our calculations, we also investigate regions of parameter space with well-established magnetic order, in particular the non-frustrated case J 2 0.68. An error analysis indicates uncertainties of order ±0.04 in the location of these critical values of J 2 . There thus is a region in parameter space without any form of magnetic order. For the unfrustrated case the results for order parameter, ground state energy, and susceptibility agree with series expansions and quantum Monte Carlo calculations to within a percent or better. Including the 16 site cluster, or analyzing the independently calculated magnetic susceptibility we also find a nonmagnetic region, but with modified values for the range of existence of the nonmagnetic region. From the leading finite-size corrections we also obtain results for the spin-wave velocity and the spin stiffness. The spin-wave velocity remains finite at the magnetic-nonmagnetic transition, as expected from the nonlinear sigma model analogy.
146 citations
TL;DR: In this paper, the degenerate frustration problem is defined in the case of discrete molecular species for which competing spin interactions lead to an orbitally degenerate ground state, with at least one magnetic component.
146 citations
04 Nov 2016
TL;DR: In this article, the authors present a direct measurement of the exchange interaction in room temperature ferromagnetic graphene and demonstrate that a proximity induced 2D ferromagnet can efficiently modulate a spin current by controlling the direction of exchange field.
Abstract: We present a direct measurement of the exchange interaction in room temperature ferromagnetic graphene. We study the spin transport in exfoliated graphene on an yttrium-iron-garnet substrate where the observed spin precession clearly indicates the presence and strength of an exchange field that is an unambiguous evidence of induced ferromagnetism. We describe the results with a modified Bloch diffusion equation and extract an average exchange field of the order of 0.2 T. Further, we demonstrate that a proximity induced 2D ferromagnet can efficiently modulate a spin current by controlling the direction of the exchange field. These findings can create a building block for magnetic-gate tuneable spin transport in one-atom-thick spintronic devices.
146 citations
TL;DR: In this paper, the authors review several proposed spintronic devices that can provide new functionality or improve available functions of electronic devices and discuss a high mobility field effect spin transistor, an all-metal spin transistor and a spin battery.
146 citations
TL;DR: In this paper, the thickness dependence of the spin current-induced ferromagnetic resonance in Ni80Fe20/nonmagnetic bilayer thin films has been investigated, showing that the spectrum shape depends on the Ni 80Fe20 layer thickness, due to extrinsic excitation in addition to spin Hall effect.
Abstract: We experimentally demonstrate the thickness dependence of the spin current-induced ferromagnetic resonance in Ni80Fe20/nonmagnetic (Pt,Pd) bilayer thin films The spectrum shape depends on the Ni80Fe20 layer thickness, due to extrinsic excitation in addition to the spin Hall effect Detailed analysis of the thickness dependence of the spectrum, both for Ni80Fe20 and nonmagnetic layers, provides the spin Hall angle (Pt: 0022±0004, Pd: 0008±0002) and spin diffusion length (Pt: 12±006 nm, Pd: 20±009 nm)
146 citations