Exchange couplings and quantum phases in two dissimilar arrays of similar copper dinuclear units

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F20%3APU136521" target="_blank" >RIV/00216305:26620/20:PU136521 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.rsc.org/en/content/articlelanding/2020/DT/D0DT00567C#!divAbstract" target="_blank" >https://pubs.rsc.org/en/content/articlelanding/2020/DT/D0DT00567C#!divAbstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d0dt00567c" target="_blank" >10.1039/d0dt00567c</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Exchange couplings and quantum phases in two dissimilar arrays of similar copper dinuclear units

Popis výsledku v původním jazyce

To investigate the magnetic properties and the spin entanglement of dinuclear arrays, we prepared compounds [{Cu(pAB)(phen)H2O}(2)NO3<bold>pABH</bold>2H(2)O], 1, and [Cu-2(pAB)(2)(phen)(2)pz](n), 2 (pABH = p-aminobenzoic acid, phen = 1,10-phenanthroline and pz = pyrazine). The structure of 1 is known and we report here that of 2. They contain similar dinuclear units of Cu-II ions with 1/2-spins S-1 and S-2 bridged by pairs of pAB molecules, with similar intradinuclear exchange and fine interactions , but different 3D crystal arrays with weak interdinuclear exchange J ', stronger in 2 than in 1. To investigate the magnetic properties and the spin entanglement produced by J ', we collected the powder spectra of 1 and 2 at 9.4 GHz and T between 5 and 298 K, and at 34.4 GHz and T = 298 K and single-crystal spectra at room T and 34.4 GHz as a function of magnetic field (B-0) orientation in three crystal planes, calculating intradinuclear magnetic parameters J(1)0 = (-75 +/- 1) cm(-1), J(2)0 = (-78 +/- 2) cm(-1), |D-(1)| = (0.142 +/- 0.006) cm(-1), |D-(2)| = (0.141 +/- 0.006) cm(-1) and E-(1) similar to E-(2) similar to 0. Single crystal data indicate a quantum entangled phase in 2 around the crossing between two fine structure EPR absorption peaks within the spin triplet. This phase also shows up in powder samples of 2 as a U-peak collecting the signals of the entangled microcrystals, a feature that allows estimating |J '|. Transitions between the two quantum phases are observed in single crystals of 2 changing the orientation of B-0. We estimate interdinuclear exchange couplings |J '((1))| < 0.003 cm(-1) and |J '((2))| = (0.013 +/- 0.005) cm(-1), in 1 and 2, respectively. Our analysis indicates that the standard approximation of a spin Hamiltonian with S = 1 for the dinuclear spectra is valid only when the interdinuclear coupling is large enough, as for compound 2 (|J '((2))/J(2)0| similar to 1.7 x 10(-4)). When J ' is negligible as in 1, the real spin Hamiltonian with

Název v anglickém jazyce

Exchange couplings and quantum phases in two dissimilar arrays of similar copper dinuclear units

Popis výsledku anglicky

To investigate the magnetic properties and the spin entanglement of dinuclear arrays, we prepared compounds [{Cu(pAB)(phen)H2O}(2)NO3<bold>pABH</bold>2H(2)O], 1, and [Cu-2(pAB)(2)(phen)(2)pz](n), 2 (pABH = p-aminobenzoic acid, phen = 1,10-phenanthroline and pz = pyrazine). The structure of 1 is known and we report here that of 2. They contain similar dinuclear units of Cu-II ions with 1/2-spins S-1 and S-2 bridged by pairs of pAB molecules, with similar intradinuclear exchange and fine interactions , but different 3D crystal arrays with weak interdinuclear exchange J ', stronger in 2 than in 1. To investigate the magnetic properties and the spin entanglement produced by J ', we collected the powder spectra of 1 and 2 at 9.4 GHz and T between 5 and 298 K, and at 34.4 GHz and T = 298 K and single-crystal spectra at room T and 34.4 GHz as a function of magnetic field (B-0) orientation in three crystal planes, calculating intradinuclear magnetic parameters J(1)0 = (-75 +/- 1) cm(-1), J(2)0 = (-78 +/- 2) cm(-1), |D-(1)| = (0.142 +/- 0.006) cm(-1), |D-(2)| = (0.141 +/- 0.006) cm(-1) and E-(1) similar to E-(2) similar to 0. Single crystal data indicate a quantum entangled phase in 2 around the crossing between two fine structure EPR absorption peaks within the spin triplet. This phase also shows up in powder samples of 2 as a U-peak collecting the signals of the entangled microcrystals, a feature that allows estimating |J '|. Transitions between the two quantum phases are observed in single crystals of 2 changing the orientation of B-0. We estimate interdinuclear exchange couplings |J '((1))| < 0.003 cm(-1) and |J '((2))| = (0.013 +/- 0.005) cm(-1), in 1 and 2, respectively. Our analysis indicates that the standard approximation of a spin Hamiltonian with S = 1 for the dinuclear spectra is valid only when the interdinuclear coupling is large enough, as for compound 2 (|J '((2))/J(2)0| similar to 1.7 x 10(-4)). When J ' is negligible as in 1, the real spin Hamiltonian with

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

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

Projekt

<a href="/cs/project/EF18_070%2F0009469" target="_blank" >EF18_070/0009469: Mezinárodní mobilita výzkumných pracovníků MSCA na VUT v Brně II</a><br>

Návaznosti

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

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

Dalton Transactions

ISSN

1477-9226

e-ISSN

1477-9234

Svazek periodika

49

Číslo periodika v rámci svazku

16

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

5228-5240

Kód UT WoS článku

000530357500027

EID výsledku v databázi Scopus

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