Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 6

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Frustration Measure for Molecular Magnets with Single-Ion Anisotropy

100%
Kozłowski P.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 3
423-425
EN
The universal frustration measure and its extension to anisotropic systems is calculated for a family of spin Hamiltonians modeling a hypothetical ring-shaped chromium-based molecular magnets. The proposed extension takes into account the impact of single-ion anisotropy on the magnetic centers and behaves more consistently with respect to the isotropic counterpart. The influence of anisotropy on both measures is assessed, which leads to a conclusion that frustration decreases with increasing absolute value of single ion anisotropy.
2
Content available remote

Closed Relation Between Single-Particle Kinetic Energy and Electron Density in One-Dimensional Two-Level Systems

63%
Kozłowski P., March N.
Acta Physica Polonica A
|
1992
|
vol. 82
|
issue 3
421-424
EN
For a two-level problem in one dimension, an implicit relation is derived relating the kinetic energy density t_{s}(x) to the electron density ρ(x) plus its first and second derivatives. As an example, the harmonic oscillator potential is used to make this relation explicit.
3
Publication available in full text mode
Content available

Fluorescence of Sodium Vapour Excited by 330 nm Laser Pulses

51%
Gorbunov N., Kozłowski P., Nowak K., Stacewicz T.
Acta Physica Polonica A
|
2001
|
vol. 99
|
issue 5
531-537
EN
We report results of investigation on the fluorescence induced in sodium vapour by pulses of laser light tuned near the 3S → 4P transition (330 nm). The fluorescence was observed in perpendicular and parallel directions in respect to the laser beam. A depletion of fluorescence intensity corresponding to the 5D → 3P transition (498 nm) was observed along the laser beam. We explain this effect as a result of reabsorption that is caused by intense population of the 3P level due to cascade stimulated processes. The most intense depletion occurs about 20 ns after the laser pulse and it corresponds to the moment of maximal population of the 3P level.
4
Content available remote

Zero Temperature Magnetic Frustration in Nona-Membered s=3/2 Spin Rings with Bond Defect

51%
Antkowiak M., Kozłowski P., Kamieniarz G.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 5-6
1102-1104
EN
Zero-temperature limits of the local and global thermodynamic quantities in the nine-membered antiferromagnetic s=3/2 spin ring are investigated by means of numerical exact diagonalization. An anisotropic Heisenberg model with tunable bond defect reflecting continuously varying topology (from closed to open ring) is exploited. The frustrated and non-frustrated phases are identified in the ground-state phase diagram determined by a bond-defect strength and magnetic field. Near the phase boundaries significance of the thermal fluctuations affecting the estimates of the local magnetic quantities found earlier at T=1 K is revealed. For the global quantities the effects of thermal fluctuations are found much weaker. A sequence of the local magnetic moments is analysed and their experimental verification at the edges of the non-frustrated and within the entire frustrated phase is suggested at sufficiently low temperature.
5
Content available remote

Modeling of the Experimental Molecular-Based Ring-Shaped Nanomagnets

39%
Antkowiak M., Kozłowski P., Musiał G., Florek W., Kamieniarz G., Esposito F.
|
|
issue 5
965-966
EN
Quantum transfer matrix technique and numerically exact diagonalization method are applied to the Heisenberg spin systems to model ring-shaped molecules. Two cases are investigated: (i) a dozen of S = 1 spins with additional biquadratic exchange and (ii) a dimetallic molecule Cr_7Cd, where it is assumed that exchange anisotropy is determined in a local coordination system. In the latter case the calculated susceptibility is compared with experimental results.
6
Content available remote

Anisotropy, Geometric Structure and Frustration Effects in Molecule-Based Nanomagnets

27%
Kamieniarz G., Kozłowski P., Antkowiak M., Sobczak P., Ślusarski T., Tomecka D., Barasiński A., Brzostowski B., Drzewiński A., Bieńko A., Mroziński J.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 5-6
992-998
EN
In this paper we review our results of comprehensive study of molecular nanomagnets recently synthesized in the form of the chromium-based molecules and bimetallic copper-containing chains as well as we present some new findings. We focus on effects of anisotropy, geometry and frustration appearing in various thermodynamic properties of the nanoscale magnets which are described by Heisenberg-like spin models and simulated by accurate numerical methods. We show that bond-dependent exchange anisotropy is needed to model magnetic torque in the Cd-doped chromium ring. We argue that only in the limit of infinite rings (n → ∞) frustration can be considered as the opposite to bipartiteness in the odd numbered (3 ≤ n ≤ 9) s = 3/2 quantum spin rings. We analyse the influence of exchange interactions and anisotropy on magnetic susceptibility of bimetallic (S = 3/2, s = 1/2) chains composed of Cu ions linked to different 3d ions by fitting experimental data. We reach the remarkable consistency of the density functional theory estimates of the magnetic couplings in Cr_8 molecule and provide strong support to the spin models exploited in the literature.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.