Fe-57 Mossbauer study of unusual magnetic structure of multiferroic 3R-AgFeO2 / Sobolev A.,Rusakov V.,Moskvin A.,Gapochka A.,Belik A.,Glazkova I.,Akulenko A.,Demazeau G.,Presniakov I. // JOURNAL OF PHYSICS-CONDENSED MATTER. - 2017. - V. 29, l. 27.

ISSN/EISSN:

0953-8984 / 1361-648X

Type:

Article

Abstract:

We report new results of a Fe-57 Mossbauer study of hyperfine magnetic interactions in the layered multiferroic 3R-AgFeO2 demonstrating two magnetic phase transitions at TN1 and TN2. The asymptotic value beta{*} approximate to 0.34 for the critical exponent obtained from the temperature dependence of the hyperfine field H-hf(T) at Fe-57 the nuclei below TN1 approximate to 14 K indicates that 3R-AgFeO2 shows quasi-3D critical behavior. The spectra just above TN1 (TN1 < T < T{*} approximate to 41 K) demonstrate a relaxation behavior due to critical spin fluctuations which indicates the occurrence of short-range correlations. At the intermediate temperature range, TN2 < T < TN1, the Fe-57 Mossbauer spectra are described in terms of collinear spin-density-waves (SDW) with the inclusion of many high-order harmonics, indicating that the real magnetic structure of the ferrite appears to be more complicated than a pure sinusoidally modulated SDW. Below T < TN2 approximate to 9 K, the hyperfine field Hhf reveals a large spatial anisotropy (Delta H-anis approximate to 30 kOe) which is related with a local intra-cluster (FeO6) spin-dipole term that implies a conventional contribution of the polarized oxygen ions. We proposed a simple two-parametric formula to describe the dependence of H-anis on the distortions of the (FeO6) clusters. Analysis of different mechanisms of spin and hyperfine interactions in 3R-AgFeO2 and its structural analogue CuFeO2 points to a specific role played by the topology of the exchange coupling and the oxygen polarization in the delafossite-like structures.

Author keywords:

multiferroics; frustrated magnetic interactions; non-collinear spin configurations; magnetostructural phase transitions; Mossbauer spectroscopy; anisotropic hyperfine magnetic interactions POINT SPIN REDUCTION; LAYER ANTIFERROMAGNET; HYPERFINE INTERACTION; CUFEO2; RELAXATION; SPECTRA; BIFEO3; FERROMAGNETS; EXCITATIONS; DIFFRACTION

DOI:

10.1088/1361-648X/aa70ae

Web of Science ID:

ISI:000403326600002

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	JUL 12
Publisher	IOP PUBLISHING LTD
Address	TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Language	English
Article-Number	275803
EISSN	1361-648X
Keywords-Plus	POINT SPIN REDUCTION; LAYER ANTIFERROMAGNET; HYPERFINE INTERACTION; CUFEO2; RELAXATION; SPECTRA; BIFEO3; FERROMAGNETS; EXCITATIONS; DIFFRACTION
Research-Areas	Physics
Web-of-Science-Categories	Physics, Condensed Matter
Author-Email	alex@radio.chem.msu.ru
ResearcherID-Numbers	Presniakov, Igor/B-8752-2009 Glazkova, Iana/A-7627-2015 Sobolev, Alexey/C-3832-2009 Gapochka, Aleksey/J-7057-2012
ORCID-Numbers	Glazkova, Iana/0000-0001-6021-3479 Sobolev, Alexey/0000-0002-8085-5425
Funding-Acknowledgement	Government of the Russian Federation {[}02.A03.21.0006]; Ministry of Education and Science of the Russian Federation {[}2277, 5719]
Funding-Text	One of the authors (ASM) acknowledges the support by the Government of the Russian Federation, Program 02.A03.21.0006 and by the Ministry of Education and Science of the Russian Federation, projects nos. 2277 and 5719.
Number-of-Cited-References	85
Usage-Count-Last-180-days	12
Usage-Count-Since-2013	12
Journal-ISO	J. Phys.-Condes. Matter
Doc-Delivery-Number	EX6BH