Magnetic skin effect in Pb(Fe _{1/2}$Nb _{1/2}$)O 3 .

Autor: Giles-Donovan N; Centre for Medical and Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Hillier AD; ISIS Facility, Rutherford Appleton Laboratory, Harwell, Didcot, United Kingdom., Ishida K; ISIS Facility, Rutherford Appleton Laboratory, Harwell, Didcot, United Kingdom.; RIKEN Nishina Center, RIKEN, Wako, Saitama, Japan., Hampshire BV; ISIS Facility, Rutherford Appleton Laboratory, Harwell, Didcot, United Kingdom.; Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom., Giblin SR; School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, United Kingdom., Roessli B; Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut (PSI), 5232 Villigen PSI, Switzerland., Gehring PM; NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6100, United States of America., Xu G; NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6100, United States of America., Li X; Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai, People's Republic of China., Luo H; Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai, People's Republic of China., Cochran S; Centre for Medical and Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Stock C; School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.
Jazyk: angličtina
Zdroj: Journal of physics. Condensed matter : an Institute of Physics journal [J Phys Condens Matter] 2024 Jul 29; Vol. 36 (43). Date of Electronic Publication: 2024 Jul 29.
DOI: 10.1088/1361-648X/ad6523
Abstrakt: Relaxor-ferroelectrics display exceptional dielectric properties resulting from the underlying random dipolar fields induced by strong chemical inhomogeneity. An unusual structural aspect of relaxors is a skin-effect where the near-surface region in single crystals exhibit structures and critical phenomena that differ from the bulk. Relaxors are unique in that this skin effect extends over a macroscopic lengthscale of ∼100 μmwhereas usual surface layers only extend over a few unit cells (or ∼nm). We present a muon spectroscopy study of Pb(Fe_{1/2}Nb_{1/2})O 3 (PFN) which displays ferroelectric order, including many relaxor-like dielectric properties such as a frequency broadened dielectric response, and antiferromagnetism with spatially short-range polar correlations and hence can be termed a multiferroic. In terms of the magnetic behavior determined by the Fe 3+ (S=5/2, L  ≈ 0) ions, PFN has been characterized as a unique example of a 'cluster spin-glass'. We use variable momentum muon spectroscopy to study the depth dependence of the slow magnetic relaxations in a large 1 cm 3 crystal of PFN. Zero-field positive muon spin relaxation is parameterized using a stretched exponential, indicative of a distribution of relaxation rates of the Fe 3+ spins. This bandwidth of frequencies changes as a function of muon momentum, indicative of a change in the Fe 3+ relaxation rates as a function of muon implantation depth in our single crystal. Using negative muon elemental analysis, we find small-to-no measurable change in the Fe 3+ /Nb 5+ concentration with depth implying that chemical concentration alone cannot account for the change in the relaxational dynamics. PFN displays an analogous magnetic skin effect reported to exist in the structural properties of relaxor-ferroelectrics.
(© 2024 IOP Publishing Ltd.)
Databáze: MEDLINE
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