Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/102119
Title: Fe-57 Mossbauer study of unusual magnetic structure of multiferroic 3R-AgFeO2
Authors: Sobolev, A.
Rusakov, V.
Moskvin, A.
Gapochka, A.
Belik, A.
Glazkova, I.
Akulenko, A.
Demazeau, G.
Presniakov, I.
Issue Date: 2017
Publisher: Institute of Physics Publishing
Citation: Fe-57 Mossbauer study of unusual magnetic structure of multiferroic 3R-AgFeO2 / A. Sobolev, V. Rusakov, A. Moskvin, et al. — DOI 10.1088/1361-648X/aa70ae // Journal of Physics Condensed Matter. — 2017. — Vol. 29. — Iss. 27. — 275803.
Abstract: We report new results of a 57Fe Mössbauer study of hyperfine magnetic interactions in the layered multiferroic 3R-AgFeO2 demonstrating two magnetic phase transitions at T N1 and T N2. The asymptotic value β ∗ ≈ 0.34 for the critical exponent obtained from the temperature dependence of the hyperfine field H hf(T) at 57Fe the nuclei below T N1 ≈ 14 K indicates that 3R-AgFeO2 shows quasi-3D critical behavior. The spectra just above T N1 (T N1 < T < T ∗ ≈ 41 K) demonstrate a relaxation behavior due to critical spin fluctuations which indicates the occurrence of short-range correlations. At the intermediate temperature range, T N2 < T < T N1, the 57Fe Mössbauer 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 < T N2 ≈ 9 K, the hyperfine field H hf reveals a large spatial anisotropy (ΔH anis ≈ 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. © 2017 IOP Publishing Ltd.
Keywords: ANISOTROPIC HYPERFINE MAGNETIC INTERACTIONS
FRUSTRATED MAGNETIC INTERACTIONS
MAGNETOSTRUCTURAL PHASE TRANSITIONS
MULTIFERROICS
MÖSSBAUER SPECTROSCOPY
NON-COLLINEAR SPIN CONFIGURATIONS
ANISOTROPY
DENSITY (OPTICAL)
IRON OXIDES
MAGNETIC STRUCTURE
SPIN DENSITY WAVES
SPIN FLUCTUATIONS
SYNTHETIC METALS
TEMPERATURE DISTRIBUTION
MAGNETIC INTERACTIONS
MAGNETOSTRUCTURAL PHASE TRANSITION
MULTIFERROICS
SPIN CONFIGURATIONS
SSBAUER SPECTROSCOPIES
MAGNETISM
URI: http://hdl.handle.net/10995/102119
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85020499750
PURE ID: 1924427
ISSN: 9538984
DOI: 10.1088/1361-648X/aa70ae
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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