Control and manipulation of quantum spin switching and spin correlations in [Tb 2 ] molecular magnet under a pulse magnetic field

2017 ◽  
Vol 439 ◽  
pp. 173-180
Author(s):  
Oleg V. Farberovich ◽  
Dmitry I. Bazhanov
2019 ◽  
Vol 116 (25) ◽  
pp. 12199-12203 ◽  
Author(s):  
Niravkumar D. Patel ◽  
Nandini Trivedi

The Kitaev model with an applied magnetic field in the H∥[111] direction shows two transitions: from a nonabelian gapped quantum spin liquid (QSL) to a gapless QSL at Hc1≃0.2K and a second transition at a higher field Hc2≃0.35K to a gapped partially polarized phase, where K is the strength of the Kitaev exchange interaction. We identify the intermediate phase to be a gapless U(1) QSL and determine the spin structure function S(k) and the Fermi surface ϵFS(k) of the gapless spinons using the density matrix renormalization group (DMRG) method for large honeycomb clusters. Further calculations of static spin-spin correlations, magnetization, spin susceptibility, and finite temperature-specific heat and entropy corroborate the gapped and gapless nature of the different field-dependent phases. In the intermediate phase, the spin-spin correlations decay as a power law with distance, indicative of a gapless phase.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Lee ◽  
S.-H. Do ◽  
W. Lee ◽  
Y. S. Choi ◽  
J. van Tol ◽  
...  

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.


2019 ◽  
Vol 7 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Hongyi Yu ◽  
Mingxing Chen ◽  
Wang Yao

Abstract When quasiparticles move in condensed matters, the texture of their internal quantum structure as a function of position and momentum can give rise to Berry phases that have profound effects on the material’s properties. Seminal examples include the anomalous Hall and spin Hall effects from the momentum-space Berry phases in homogeneous crystals. Here, we explore a conjugate form of the electron Berry phase arising from the moiré pattern: the texture of atomic configurations in real space. In homobilayer transition metal dichalcogenides, we show that the real-space Berry phase from moiré patterns manifests as a periodic magnetic field with magnitudes of up to hundreds of Tesla. This quantity distinguishes moiré patterns from different origins, which can have an identical potential landscape, but opposite quantized magnetic flux per supercell. For low-energy carriers, the homobilayer moirés realize topological flux lattices for the quantum-spin Hall effect. An interlayer bias can continuously tune the spatial profile of the moiré magnetic field, whereas the flux per supercell is a topological quantity that can only have a quantized jump observable at a moderate bias. We also reveal the important role of the non-Abelian Berry phase in shaping the energy landscape in small moiré patterns. Our work points to new possibilities to access ultra-high magnetic fields that can be tailored to the nanoscale by electrical and mechanical controls.


2017 ◽  
Vol 164 ◽  
pp. 01004
Author(s):  
Jacek Ciborowski ◽  
Paweł Caban ◽  
Michał Drągowski ◽  
Joachim Enders ◽  
Yuliya Fritzsche ◽  
...  

Author(s):  
I.A. Belyaeva ◽  
◽  
L.I. Bashirova ◽  
V.A. Glushchenkov ◽  
N.A. Rodenko ◽  
...  

It was found that the pharmaceutical preparation of pentoxifylline, treated with a pulsed magnetic field (PMF), changes the antiaggregatory properties.The pharmaceutical preparation contains the pure substance of pentoxifylline and a number of excipients. To understand the mechanism of changes in the antiaggregatory activity of a pharmaceutical preparation, the goal was to further investigate the effect of PMF parameters on its chemically pure substance.PMF processing was carried out on the «MIU Bio» installation with a single exposure at a field strength in the range (0.48–1.17) 106 A/m at discharge circuit frequencies (8–50) 103 Hz.Experiments have shown that the effect of PMF on the pure substance of pentoxifylline did not cause significant changes in its antiaggregatory activity. This result made it possible to get one step closer to understanding the mechanism of the effect of PMF on a given drug. Apparently, the reason for the change in the biological effectiveness of the pharmaceutical pentoxifylline treated with PMF lies in the effect of impurities, which will be the focus of further research.


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