Magnetic-field-tuned phase transition of a molecular material from the isolated-spin to the coupled-spin regime

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F19%3APU131087" target="_blank" >RIV/00216305:26620/19:PU131087 - isvavai.cz</a>

Result on the web

<a href="https://pubs.rsc.org/en/content/articlelanding/2019/cp/c8cp06719h#!divAbstract" target="_blank" >https://pubs.rsc.org/en/content/articlelanding/2019/cp/c8cp06719h#!divAbstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c8cp06719h" target="_blank" >10.1039/c8cp06719h</a>

Result language

angličtina

Original language name

Magnetic-field-tuned phase transition of a molecular material from the isolated-spin to the coupled-spin regime

Original language description

We report the preparation, X-ray structure, chemical properties, and electron paramagnetic resonance (EPR) studies at Q and X-bands and temperature (mainly) T = 293 K of powder and oriented single crystal samples of the new compound [Cu(N0 ,N0-dimethyl-N0-benzoylthiourea)(2,20-bipyridine)Cl], called CuBMB. The EPR spectra of single crystal samples at the Q-band display abrupt merging and narrowing of the peaks corresponding to two rotated copper sites as a function of magnetic field (B0) orientation. This behaviour indicates a quantum transition from an array of quasi-isolated spins to a quantumentangled spin array associated with exchange narrowing processes and produced by weak intermolecular exchange interactions Ji between neighbour copper spins. This transition occurs when the magnitudes of the anisotropic contributions to the Zeeman couplings, tuned with the direction of B0, approach these |Ji| and produce level crossings. The exchange couplings between neighbour spins are estimated from the angular variation of the single crystal EPR results at the Q-band. We analyse the quantum behaviour and phase transitions of the spin system and discuss the magnitudes of the exchange couplings in terms of the structure of the chemical paths connecting Cu neighbours. The single crystal data at the Q-band indicates an uncommon ground electronic state of CuII which is discussed and compared with the results of DFT calculations. The spectrum of polycrystalline (powder) samples at the Q-band is a sum of contributions of microcrystals in each phase, and the fraction F of the entangled phase depends on the microwave frequency. The X-band spectrum is compatible with the Q-band results, but does not display a transition, and the spin system is in the quantum-entangled phase for all field orientations. This behaviour is further studied with a simple geometric model giving basic predictions. The crystal structure of CuBMB is monoclinic, space group P21/n, with a = 11.9790(3) Å, b =

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10301 - Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)

Project

<a href="/en/project/EF18_070%2F0009469" target="_blank" >EF18_070/0009469: International mobility of researchers - MSCA - BUT - II</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

1463-9084

Volume of the periodical

21

Issue of the periodical within the volume

8

Country of publishing house

GB - UNITED KINGDOM

Number of pages

14

Pages from-to

4394-4407

UT code for WoS article

000461722500026

EID of the result in the Scopus database

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