Low-spin S=1/2 ground state of the Cu trimers in the paper-chain compound Ba3Cu3In4O12 / Gippius A. A.,Gervits N. E.,Tkachev A. V.,Maslova I. S.,Volkova O. S.,Vasiliev A. N.,Buettgen N.,Kraetschmer W.,Moskvin A. S. // PHYSICAL REVIEW B. - 2012. - V. 86, l. 15.

ISSN/EISSN:

1098-0121 / нет данных

Type:

Article

Abstract:

The magnetic ground states of the isostructural paper-chain compounds Ba3Cu3In4O12 and Ba3Cu3Sc4O12 were recently found to be ordered antiferromagnetically (AFM), while both quantum magnets reveal positive asymptotic Curie-Weiss temperatures suggestive of ferromagnetic (FM) interactions at high temperatures. Due to the AFM-FM competition the saturation magnetization in both compounds is reached already in modest magnetic fields with a nontrivial succession of two spin-flop and two spin-flip-like transitions in Ba3Cu3In4O12. We argue that the paper-chains in both compounds can be described as a system of Cu-I-2Cu(II) trimers with a low-spin S = 1/2 ground state which implies a nonmagnetic spin-singlet Cu-II dimer state and a spin-polarized Cu-I ion. To validate the model we performed extensive nuclear resonance-nuclear quadrupole resonance-nuclear magnetic resonance (NQR-NMR)-measurements in Ba3Cu3In4O12. Two different types of (63),Cu-65 nuclear resonance spectra were observed in the magnetically ordered state at zero external magnetic field: (i) a pure NQR spectrum in the frequency range of 24-30 MHz and (ii) a zero-field NMR spectrum in the frequency range of 50-65 MHz. This result unambiguously indicates that one of the two types of copper ions in Ba3Cu3In4O12 is in a nonmagnetic spin state below T-N. It provides a unique criterion to test any theoretical model describing the ground-state spin structure in Ba3Cu3In4O12. We attribute the pure NQR spectrum to Cu-II ions forming nonmagnetic spin-singlet Cu-2(II) dimers and the zero-field NMR spectrum to spin-polarized Cu-I ions. Both NQR and zero-field NMR spectra point to an existence of at least two nonequivalent sets of the copper trimers, probably due to displacements of the Cu-I ions along the cavity in the c direction.

Author keywords:

RESONANCE; OXIDES; NQR; NMR

DOI:

10.1103/PhysRevB.86.155114

Web of Science ID:

ISI:000309579100001

Соавторы в МНС:

Другие поля

Поле	Значение
Month	OCT 9
Publisher	AMER PHYSICAL SOC
Address	ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Language	English
Article-Number	155114
Keywords-Plus	RESONANCE; OXIDES; NQR; NMR
Research-Areas	Physics
Web-of-Science-Categories	Physics, Condensed Matter
ResearcherID-Numbers	Vasiliev, Alexander/A-7562-2008 Volkova, Olga/A-4072-2008 Gippius, Andrey/D-1139-2010
ORCID-Numbers	Vasiliev, Alexander/0000-0003-3558-6761 Volkova, Olga/0000-0001-7853-4801
Funding-Acknowledgement	RFBR {[}0-02-00021, 10-02-96032, 11-02-92707-IND, 12-02-01039]; DFG (Augsburg-Munich) {[}TRR 80]
Funding-Text	This work was partially supported by the RFBR Grants No. 10-02-00021, No. 10-02-96032, No. 11-02-92707-IND, and No. 12-02-01039. N.B., W.K., and A.G. acknowledge the support of the DFG via TRR 80 (Augsburg-Munich).
Number-of-Cited-References	19
Usage-Count-Since-2013	18
Journal-ISO	Phys. Rev. B
Doc-Delivery-Number	017GW