Normal modes of a spin cycloid or helix

Fishman, Randy; Rõõm, T.; Sousa, Rogério de

doi:10.1103/physrevb.99.064414

Cited by 10 publications

(9 citation statements)

References 37 publications

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“…The spin configuration for a = 0.55 in Fig. 3(b) is shown in 3(d), which clearly exhibits cycloidal correlations on the xy-plane similar to those found in different systems [42]. Despite the small size (L = 14) of the chains shown so far, they exhibit the main features of larger systems in this regime.…”

supporting

confidence: 61%

Competing long-range interactions and spin vector chirality in spin-chains

Vernek,

Ávalos-Ovando,

Ulloa

2020

Preprint

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Studies of competing orders in 1D magnetic chains have attracted considerable attention in recent years, as the presence of long-range Heisenberg interactions is found to allow interesting quantum phase transitions. We investigate here the role of spin-orbit effects by considering spin-1/2 chains in the presence of both collinear and non-collinear long-range interactions. By employing exact diagonalization and density matrix renormalization group calculations we investigate the rich phase diagram of this system. We find transitions from collinear to transverse magnetic correlated order as the strength of the non-collinear coupling increases, accompanied by a jump in the vector spin chirality order parameter of the system. This shows that tuning long-range interactions allows control of the onset of sizable vector spin chirality in a system, which may be used to transmit information down the chain. We investigate the characteristic structure of the distinct phases and explore their possible physical implementation in different materials systems.

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supporting

confidence: 61%

Competing long-range interactions and spin vector chirality in spin-chains

Vernek,

Ávalos-Ovando,

Ulloa

2020

Preprint

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“…where V 0 is a constant, a is the lattice parameter, J is the exchange constant, and n n is the direction vector, oriented along one of the <100> crystallographic axes. Here, we used an assumption that the Heisenberg exchange constant remains unchanged, which is a commonly used approximation for multiferroic BiFeO 3 ; in particular, the deviation (noncollinearity) of the nearest-neighbor spins is accounted for by the antisymmetric Dzyaloshinskii-Moriya exchange interaction [42,43]. AFM spin arrangement is superimposed with a spatially modulated magnetic structure with a large period λ = (620 ± 20 Å) incommensurate with the lattice parameter [44].…”

Section: Multiferroic Bifeomentioning

confidence: 99%

Symmetry Analysis of Magnetoelectric Effects in Perovskite-Based Multiferroics

Gareeva

Zvezdin

et al. 2022

Materials

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In this article, we performed symmetry analysis of perovskite-based multiferroics: bismuth ferrite (BiFeO3)-like, orthochromites (RCrO3), and Ruddlesden–Popper perovskites (Ca3Mn2O7-like), being the typical representatives of multiferroics of the trigonal, orthorhombic, and tetragonal crystal families, and we explored the effect of crystallographic distortions on magnetoelectric properties. We determined the principal order parameters for each of the considered structures and obtained their invariant combinations consistent with the particular symmetry. This approach allowed us to analyze the features of the magnetoelectric effect observed during structural phase transitions in BixR1−xFeO3 compounds and to show that the rare-earth sublattice has an impact on the linear magnetoelectric effect allowed by the symmetry of the new structure. It was shown that the magnetoelectric properties of orthochromites are attributed to the couplings between the magnetic and electric dipole moments arising near Cr3+ ions due to distortions linked with rotations and deformations of the CrO6 octahedra. For the first time, such a symmetry consideration was implemented in the analysis of the Ruddlesden–Popper structures, which demonstrates the possibility of realizing the magnetoelectric effect in the Ruddlesden–Popper phases containing magnetically active cations, and allows the estimation of the conditions required for its optimization.

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“…Charge disproportionation to Fe(III) and Fe(V) was observed by Mössbauer spectroscopy 95,96 . Spiral magnetic order was observed by neutron diffraction 97 and provides a rare example of a magnetic cycloid arising from a ferromagnetic nearest neighbor competing with antiferromagnetic next-nearest exchange 98 . Further interest in this material arise from high oxygen mobility 99 .…”

Section: Application Of Rvae To a Layered Perovskitementioning

confidence: 99%

“…65,66 Spiral magnetic order was observed by neutron diffraction 67 and provides a rare example of a magnetic cycloid arising from a ferromagnetic nearest neighbor competing with antiferromagnetic nextnearest exchange. 68 Further interest in this material arise from high oxygen mobility. 69 The preparation of a near stoichiometric compound requires high oxygen partial pressure.…”

Section: Bayesian Local Crystallographymentioning

confidence: 99%

Deep Bayesian local crystallography

et al. 2021

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The advent of high-resolution electron and scanning probe microscopy imaging has opened the floodgates for acquiring atomically resolved images of bulk materials, 2D materials, and surfaces. This plethora of data contains an immense volume of information on materials structures, structural distortions, and physical functionalities. Harnessing this knowledge regarding local physical phenomena necessitates the development of the mathematical frameworks for extraction of relevant information. However, the analysis of atomically resolved images is often based on the adaptation of concepts from macroscopic physics, notably translational and point group symmetries and symmetry lowering phenomena. Here, we explore the bottom-up definition of structural units and symmetry in atomically resolved data using a Bayesian framework. We demonstrate the need for a Bayesian definition of symmetry using a simple toy model and demonstrate how this definition can be extended to the experimental data using deep learning networks in a Bayesian setting, namely rotationally invariant variational autoencoders.

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Normal modes of a spin cycloid or helix

Cited by 10 publications

References 37 publications

Competing long-range interactions and spin vector chirality in spin-chains

Competing long-range interactions and spin vector chirality in spin-chains

Symmetry Analysis of Magnetoelectric Effects in Perovskite-Based Multiferroics

Deep Bayesian local crystallography

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