Magnetoelectric control of frozen state in a toroidal glass

Yamaguchi, Yasuhiro; Kimura, T.

doi:10.1038/ncomms3063

Cited by 38 publications

(32 citation statements)

References 25 publications

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“…Today, the range of static toroidal systems under study includes various compounds 34,35 , boracites 36 , pyroxines 37 and olivines 38 , metals 39 , glasses 40 , ferroelectric nanoscale disks and rods 27 , molecular magnets 41,42 . However, unambiguous observations of long-range toroidal order have proven challenging due to the weak, short-range interactions between toroidal dipoles and the requirement of simultaneously breaking both space and time reversal symmetry to demonstrate its existence 18 .…”

Section: Static Toroidal Multipolesmentioning

confidence: 99%

Electromagnetic toroidal excitations in matter and free space

et al. 2016

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The toroidal dipole is a localized electromagnetic excitation, distinct from the magnetic and electric dipoles. While the electric dipole can be understood as a pair of opposite charges and the magnetic dipole as a current loop, the toroidal dipole corresponds to currents flowing on the surface of a torus. Toroidal dipoles provide physically significant contributions to the basic characteristics of matter including absorption, dispersion, and optical activity. Toroidal excitations also exist in free-space as spatially and temporally localized electromagnetic pulses propagating at the speed of light and interacting with matter. We review recent experimental observations of resonant toroidal dipole excitations in metamaterials and the discovery of anapoles, non-radiating current configurations involving toroidal dipoles. While certain fundamental and practical aspects of toroidal electrodynamics remain open for the moment, we envision that exploitation of toroidal response can have important implications for the fields of photonics, sensing, energy and information. IntroductionThe interactions of electromagnetic radiation with matter underpin some of the most important technologies today -from telecommunications to information processing and data storage; from spectroscopy and imaging to light-assisted manufacturing. Our understanding and description of the electromagnetic properties of matter traditionally involves the concept of electric and magnetic dipoles, as well as their more complex combinations, known as multipoles. Introduced by Maxwell and Lorentz and later refined by Jackson and Landau, this framework, termed the multipole expansion, is central in physics and is being routinely applied in the study of optical, condensed matter, atomic, nuclear phenomena and beyond 1 . Within this framework, electromagnetic media can be represented by a set of point-like multipole sources [2][3][4][5] . The commonly used set of multipoles comprises the electric and magnetic families, which can be represented by oscillating charges and loop currents respectively. Dynamic toroidal multipoles constitute a third independent family of elementary electromagnetic sources, rather than an alternative multipole expansion or higher-order corrections to the conventional electric and magnetic multipoles (see tutorial inset I).Introduced in 1958 by Y. B. Zeldovich, toroidal moments have been considered in systems of toroidal topology (see Fig. 1) and studied in the context of nuclear 6 , atomic 7 , and molecular physics 8 , classical electrodynamics 9,10 , and solid state physics 3 . In the field of electromagnetism, in particular, a number of works have led to the development of a complete theoretical framework for toroidal electrodynamics [11][12][13][14][15] and the prediction of exotic effects, including dynamic non-radiating charge current configurations 10 and non-reciprocal interactions 9 . Following recent experimental observations of toroidal contributions in the response of materials across the electromagnetic spectrum, dyn...

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Section: Static Toroidal Multipolesmentioning

confidence: 99%

Electromagnetic toroidal excitations in matter and free space

et al. 2016

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“…They used a simple Landau free energy argument to show how the magnetoelectric effect arises. However, doping with even a small amount of Ni 2+ into the Mn 2+ site substantially changes both the magnetic and electrical properties of the system [18,20,22], which complicates the mechanism for magnetoelectric behaviour.…”

Section: -Introductionmentioning

confidence: 99%

“…[15] But, over the last eight years MnTiO3 has once again been the subject of scientific scrutiny for its strong magnetoelectric properties. [16][17][18][19][20][21][22] Mufti et al [16] showed that the application of electric and magnetic fields along the c-axis results in a strong dielectric anomaly and pyroelectric current up until the spin flop transition. They used a simple Landau free energy argument to show how the magnetoelectric effect arises.…”

Section: -Introductionmentioning

confidence: 99%

Incommensurate crystal supercell and polarization flop observed in the magnetoelectric ilmeniteMnTiO3

Silverstein¹,

Skoropata²,

Sarte³

et al. 2016

Phys. Rev. B

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MnTiO3 has been studied for many decades, but it was only in the last few years that its strong magnetoelectric behavior had been observed. Here, we use neutron scattering on two separately grown single crystals and two powder samples to show the presence of a supercell that breaks R-3 symmetry. We also present the temperature and field dependence of the dielectric constant and pyroelectric current, and show evidence of non-zero off-diagonal magnetoelectric tensor elements (forbidden by R-3 symmetry) followed by a polarization flop accompanying the spin flop transition at μ0HSF = 6.5 T. Mössbauer spectroscopy on MnTiO3 gently doped with 57 Fe was used to help shed light on the impact of the supercell on the observed behavior. Although the full supercell structure could not be solved at this time due to a lack of visible reflections, the full-scope of the results presented here suggest that the role of local spin-lattice coupling in the magnetoelectric properties of MnTiO3 is likely more important than previously thought.

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“…For the ilmenite structure of the XY-like spin glass Ni x Mn 1−x TiO 3 (x ≈ 0.42), the Ni 2+ and Mn 2+ ions are randomly distributed in the magnetic (Ni, Mn) plane and form a honey comb lattice. At the presence of the cross-product of the electric and magnetic field components, a net toroidal moment is polarized in the direction perpendicular to the honeycomb lattices during the spin-freezing process (in Figure 2B) [81].…”

Section: Toroidization and Me In Materialsmentioning

confidence: 99%

“…A static toroidal moment exists in various materials both microscopically and macroscopically, covering transition metal ions [68], biological and chemical macromolecules [69][70][71][72][73][74], bulk crystals [75][76][77][78][79][80], and glasses [81]. In macroscopic condensed matter, formation of toroidal moments in materials plays a vital role in the asymmetric ME.…”

Section: Toroidization and Me In Materialsmentioning

confidence: 99%

Theory and applications of toroidal moments in electrodynamics: their emergence, characteristics, and technological relevance

2017

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Dipole selection rules underpin much of our understanding in characterization of matter and its interaction with external radiation. However, there are several examples where these selection rules simply break down, for which a more sophisticated knowledge of matter becomes necessary. An example, which is increasingly becoming more fascinating, is macroscopic toroidization (density of toroidal dipoles), which is a direct consequence of retardation. In fact, dissimilar to the classical family of electric and magnetic multipoles, which are outcomes of the Taylor expansion of the electromagnetic potentials and sources, toroidal dipoles are obtained by the decomposition of the moment tensors. This review aims to discuss the fundamental and practical aspects of the toroidal multipolar moments in electrodynamics, from its emergence in the expansion set and the electromagnetic field associated with it, the unique characteristics of their interaction with external radiations and other moments, to the recent attempts to realize pronounced toroidal resonances in smart configurations of meta-molecules. Toroidal moments not only exhibit unique features in theory but also have promising technologically relevant applications, such as data storage, electromagnetic-induced transparency, unique magnetic responses and dichroism.

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Magnetoelectric control of frozen state in a toroidal glass

Cited by 38 publications

References 25 publications

Electromagnetic toroidal excitations in matter and free space

Electromagnetic toroidal excitations in matter and free space

Incommensurate crystal supercell and polarization flop observed in the magnetoelectric ilmeniteMnTiO3

Theory and applications of toroidal moments in electrodynamics: their emergence, characteristics, and technological relevance

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