Role of quadratic terms in the Heisenberg model for quantum spin dynamics

2011 ◽  
Vol 84 (5) ◽  
Author(s):  
R. Wieser
Keyword(s):  
Heisenberg Model ◽  
Spin Dynamics ◽  
Quantum Spin

scholarly journals Dichotomy in temporal and thermal spin correlations observed in the breathing pyrochlore LiGa1−xInxCr4O8

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Lee ◽  
S.-H. Do ◽  
W. Lee ◽  
Y. S. Choi ◽  
J. van Tol ◽  
...  
Keyword(s):  
Time Scale ◽  
Spin Dynamics ◽  
Muon Spin ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Fast Time ◽  
Spin Liquids ◽  
Magnetic Ground State ◽  
Spin Correlations ◽  
Magnetic Specific Heat

AbstractA breathing pyrochlore system is predicted to host a variety of quantum spin liquids. Despite tremendous experimental and theoretical efforts, such sought-after states remain elusive as perturbation terms and lattice distortions lead to magnetic order. Here, we utilize bond alternation and disorder to tune a magnetic ground state in the Cr-based breathing pyrochlore LiGa1−xInxCr4O8. By combining thermodynamic and magnetic resonance techniques, we provide experimental signatures of a spin-liquid-like state in x = 0.8, namely, a nearly T2-dependent magnetic specific heat and persistent spin dynamics by muon spin relaxation (μSR). Moreover, 7Li NMR, ZF-μSR, and ESR unveil the temporal and thermal dichotomy of spin correlations: a tetramer singlet on a slow time scale vs. a spin-liquid-like state on a fast time scale. Our results showcase that a bond disorder in the breathing pyrochlore offers a promising route to disclose exotic magnetic phases.

scholarly journals Transverse Spin Dynamics in the Anisotropic Heisenberg Model Realized with Ultracold Atoms

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Paul Niklas Jepsen ◽  
Wen Wei Ho ◽  
Jesse Amato-Grill ◽  
Ivana Dimitrova ◽  
Eugene Demler ◽  
...  
Keyword(s):  
Heisenberg Model ◽  
Ultracold Atoms ◽  
Spin Dynamics ◽  
Transverse Spin ◽  
Anisotropic Heisenberg Model

scholarly journals All-optical study of tunable ultrafast spin dynamics in [Co/Pd]/NiFe systems: the role of spin-twist structure on Gilbert damping

RSC Advances ◽  
2016 ◽  
Vol 6 (83) ◽  
pp. 80168-80173 ◽  
Author(s):  
Chandrima Banerjee ◽  
Semanti Pal ◽  
Martina Ahlberg ◽  
T. N. Anh Nguyen ◽  
Johan Åkerman ◽  
...  
Keyword(s):  
Spin Dynamics ◽  
Optical Study ◽  
Gilbert Damping ◽  
Spin Configuration ◽  
Exchange Spring ◽  
Static Spin ◽  
All Optical ◽  
Magnetization Precession ◽  
Twist Structure

The competing magnetic anisotropies and the interfacial properties are found to control the static spin configuration and ultrafast demagnetization, magnetization precession and damping in [Co/Pd]/NiFe(t) exchange spring samples.

Magnetic Excitations

2020 ◽  
pp. 257-310
Author(s):  
Andrew T. Boothroyd
Keyword(s):  
Crystal Field ◽  
Spin Dynamics ◽  
Random Phase ◽  
Wave Theory ◽  
Quantum Spin ◽  
Dynamical Response ◽  
Magnetic Clusters ◽  
Quantum Spin Chains ◽  
Magnetic Systems ◽  
Scattering Spectrum

In this chapter, the neutron inelastic scattering spectrum is calculated for a variety of magnetic systems. A number of isolated magnetic systems are considered, including single-ion crystal field and intermultiplet excitations, and magnetic clusters. Linear spin-wave theory, a method for calculating the collective spin dynamics in magnetically ordered systems, is outlined and applied to ferromagnets and antiferromagnets both with and without anisptropy. The Random Phase Approximation (RPA) method for the generalized susceptibility is presented and applied to calculate the spectrum of crystal field excitons in praseodymium. The nature of the spin excitations in itinerant magnets is described, and the generalized susceptibility is calculated in the RPA for itinerant electrons with echange correlations. General features of the spin dynamical response in quantum magnets are described, and illustrated by the magnetic spectra of quantum spin chains.

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