scholarly journals Longitudinal Spin Dynamics in the Heisenberg Antiferromagnet: Two-Magnon Excitations

2020 ◽  
Vol 65 (10) ◽  
pp. 865
Author(s):  
O. O. Boliasova ◽  
V. N. Krivoruchko
Keyword(s):  
Wave Vector ◽  
Spin Dynamics ◽  
Laser Pulses ◽  
Magnetization Dynamics ◽  
Longitudinal Magnetization ◽  
Fundamental Limits ◽  
Ultrafast Laser Pulses ◽  
Diagrammatic Technique ◽  
Antiferromagnetic Materials ◽  
Longitudinal Spin

Understanding the ultrafast spin dynamics in magnetically ordered materials is important for the comprehenssion of fundamental limits in spin-based magnetic electronics – magnonics. We have studied a microscopic model of magnetization dynamics in a two-sublattice antiferromagnet with the emphasis on longitudinal spin excitations. The diagrammatic technique for spin operators has been used to overcome limitations typical of phenomenological approaches. The graphical representations of spin wave propagators allow us to summing up the infinite series of distinctive diagrams. Its sum is transformed into an analytic expression for the longitudinal spin susceptibility xzz (q, w) applicable in all regions of the frequency w and wave vector q spaces beyond the hydrodynamical and critical regimes. It is found that the longitudinal magnetization dynamics consists of two types of excitations, which have different dependences on the temperature and wave vector q. The obtained result could be important for understanding the physics of nonequilibrium magnetic dynamics under the effect of ultrafast laser pulses in antiferromagnetic materials.

scholarly journals Magnetisation Processes in Geometrically Frustrated Spin Networks with Self-Assembled Cliques

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 336 ◽  
Author(s):  
Bosiljka Tadić ◽  
Miroslav Andjelković ◽  
Milovan Šuvakov ◽  
Geoff J. Rodgers
Keyword(s):  
Domain Walls ◽  
Spin Dynamics ◽  
Higher Order ◽  
Spin Networks ◽  
Graph Theoretic ◽  
Geometrically Frustrated ◽  
Geometric Frustration ◽  
Antiferromagnetic Materials ◽  
Geometrically Constrained ◽  
Ferromagnetic Interactions

Functional designs of nanostructured materials seek to exploit the potential of complex morphologies and disorder. In this context, the spin dynamics in disordered antiferromagnetic materials present a significant challenge due to induced geometric frustration. Here we analyse the processes of magnetisation reversal driven by an external field in generalised spin networks with higher-order connectivity and antiferromagnetic defects. Using the model in (Tadić et al. Arxiv:1912.02433), we grow nanonetworks with geometrically constrained self-assemblies of simplexes (cliques) of a given size n, and with probability p each simplex possesses a defect edge affecting its binding, leading to a tree-like pattern of defects. The Ising spins are attached to vertices and have ferromagnetic interactions, while antiferromagnetic couplings apply between pairs of spins along each defect edge. Thus, a defect edge induces n − 2 frustrated triangles per n-clique participating in a larger-scale complex. We determine several topological, entropic, and graph-theoretic measures to characterise the structures of these assemblies. Further, we show how the sizes of simplexes building the aggregates with a given pattern of defects affects the magnetisation curves, the length of the domain walls and the shape of the hysteresis loop. The hysteresis shows a sequence of plateaus of fractional magnetisation and multiscale fluctuations in the passage between them. For fully antiferromagnetic interactions, the loop splits into two parts only in mono-disperse assemblies of cliques consisting of an odd number of vertices n. At the same time, remnant magnetisation occurs when n is even, and in poly-disperse assemblies of cliques in the range n ∈ [ 2 , 10 ] . These results shed light on spin dynamics in complex nanomagnetic assemblies in which geometric frustration arises in the interplay of higher-order connectivity and antiferromagnetic interactions.

Cloning assay thresholds on cells exposed to ultrafast laser pulses

1999 ◽  
Author(s):  
Karsten Koenig ◽  
Iris Riemann ◽  
Peter Fischer ◽  
Thomas P. Becker ◽  
Hartmut Oehring ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Ultrafast Laser ◽  
Ultrafast Laser Pulses ◽  
Cloning Assay

scholarly journals Complete elimination of nonlinear light-matter interactions with broadband ultrafast laser pulses

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
Chuan-Cun Shu ◽  
Daoyi Dong ◽  
Ian R. Petersen ◽  
Niels E. Henriksen
Keyword(s):  
Laser Pulses ◽  
Ultrafast Laser ◽  
Complete Elimination ◽  
Ultrafast Laser Pulses

scholarly journals Manifestations of induced molecular alignment in the interaction of ultrafast laser pulses with gases

2017 ◽  
Vol 826 ◽  
pp. 012001
Author(s):  
A A Kolomenskii ◽  
N Kaya ◽  
G Kaya ◽  
M Sayrac ◽  
Y Boran ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Molecular Alignment ◽  
Ultrafast Laser ◽  
Ultrafast Laser Pulses

Ultrafast Laser Pulses Enable One‐Step Graphene Patterning on Woods and Leaves for Green Electronics

2019 ◽  
Vol 29 (33) ◽  
pp. 1902771 ◽  
Author(s):  
Truong‐Son Dinh Le ◽  
Sangbaek Park ◽  
Jianing An ◽  
Pooi See Lee ◽  
Young‐Jin Kim
Keyword(s):  
Laser Pulses ◽  
Ultrafast Laser ◽  
Ultrafast Laser Pulses ◽  
One Step ◽  
Green Electronics

scholarly journals Extended depth of focus multiphoton microscopy via incoherent pulse splitting

2020 ◽  
Author(s):  
Bingying Chen ◽  
Tonmoy Chakraborty ◽  
Stephan Daetwyler ◽  
James D. Manton ◽  
Kevin Dean ◽  
...  
Keyword(s):  
Multiphoton Microscopy ◽  
Laser Pulses ◽  
Low Complexity ◽  
Phase Mask ◽  
Light Sources ◽  
Depth Of Focus ◽  
Ultrafast Laser Pulses ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Extended Depth Of Focus

AbstractWe present a phase mask that can be easily added to any multi-photon raster scanning microscope to extend the depth of focus five-fold at a small loss in lateral resolution. The method is designed for ultrafast laser pulses or other light-sources featuring a low coherence length. In contrast to other methods of focus extension, our approach uniquely combines low complexity, high light-throughput and multicolor capability. We characterize the point-spread function in a two-photon microscope and demonstrate fluorescence imaging of GFP labeled neurons in fixed brain samples as imaged with conventional and extended depth of focus two-photon microscopy.

scholarly journals Shaped ultrafast laser pulses in the deep ultraviolet

2007 ◽  
Vol 15 (7) ◽  
pp. 4385 ◽  
Author(s):  
Brett J. Pearson ◽  
Thomas C. Weinacht
Keyword(s):  
Laser Pulses ◽  
Ultrafast Laser ◽  
Ultrafast Laser Pulses ◽  
Deep Ultraviolet
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