Spin-wave dynamics and exchange interactions in multiferroic NdFe3(BO3)4 explored by inelastic neutron scattering

Golosovsky, I. V.; Ovsyanikov, A.K.; Aristov, D. N.; Matveeva, Polina; Mukhin, A. A.; Boehm, Martin; Regnault, L.P.; Безматерных, Л. Н.

doi:10.1016/j.jmmm.2017.10.065

Cited by 11 publications

(3 citation statements)

References 34 publications

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“…A few decades ago Yamaguchi proposed and analyzed a model, which took into account all symmetric and antisymmetric exchange interactions within the Fe sublattice as well as interactions between Fe and R sublattices, whereas the interactions and anisotropy within the R sublattice were neglected [38]. The excitation spectrum of this model consists of a number of entangled collective Fe-R spinwave modes, as was shown for many other compounds with magnetic interaction between different sublattices [40][41][42][43][44][45].…”

Section: A Magnetic Hamiltonian Of Ybfeomentioning

confidence: 99%

Decoupled spin dynamics in the rare-earth orthoferrite YbFeO3 : Evolution of magnetic excitations through the spin-reorientation transition

Nikitin

Sefat

et al. 2018

Phys. Rev. B

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In this paper we present a comprehensive study of magnetic dynamics in the rare-earth orthoferrite YbFeO 3 at temperatures below and above the spin-reorientation (SR) transition T SR = 7.6 K, in magnetic fields applied along the a, b and c axes. Using single-crystal inelastic neutron scattering, we observed that the spectrum of magnetic excitations consists of two collective modes well separated in energy: 3D gapped magnons with a bandwidth of ∼60 meV, associated with the antiferromagnetically (AFM) ordered Fe subsystem, and quasi-1D AFM fluctuations of ∼1 meV within the Yb subsystem, with no hybridization of those modes. The spin dynamics of the Fe subsystem changes very little through the SR transition and could be well described in the frame of semiclassical linear spin-wave theory. On the other hand, the rotation of the net moment of the Fe subsystem at T SR drastically changes the excitation spectrum of the Yb subsystem, inducing the transition between two regimes with magnon and spinon-like fluctuations. At T < T SR , the Yb spin chains have a well defined field-induced ferromagnetic (FM) ground state, and the spectrum consists of a sharp single-magnon mode, a two-magnon bound state, and a two-magnon continuum, whereas at T > T SR only a gapped broad spinon-like continuum dominates the spectrum. In this work we show that a weak quasi-1D coupling within the Yb subsystem J Yb-Yb , mainly neglected in previous studies, creates unusual quantum spin dynamics on the low energy scales. The results of our work may stimulate further experimental search for similar compounds with several magnetic subsystems and energy scales, where low-energy fluctuations and underlying physics could be "hidden" by a dominating interaction. entropy evolution [9], laser-pulse induced ultrafast spinreorientation [10-12] etc. Magnetic property investigations of the rare-earth orthoferrites RFeO 3 have shown that the Fe 3+ moments (S = 5 2 ) are ordered in a canted AFM structure Γ 4 at high temperature with T N ≈ 600 K (details of the notations are given in [13]), and the spin canting gives a weak net ferromagnetic moment along the c axis [ Fig. 1(c)] [13][14][15]. Furthermore, symmetry analysis and careful neutron diffraction measurements have found a second "hidden" canting along the b-axis, which is symmetric relative to the ac-plane and does not create a net moment [16,17]. With decreasing temperature, a spontaneous spin-reorientation (SR) transition from Γ 4 to the Γ 2 magnetic configuration occurs in many orthoferrites with magnetic R-ions [13,14] in a wide temperature range from T SR ≈ 450 K for SmFeO 3 down to T SR ≈ 7.6 K for YbFeO 3 , and the net magnetic moment rotates from the a to the c axis [see Fig. 1(c-e)]. Most of previous work that was devoted to the investigation of the SR transition in RFeO 3 , associated this phenomenon with the R-Fe exchange interaction, because orthoferrites with nonmagnetic R =La, Y or Lu preserve the Γ 4 magnetic structure down to the lowest temperatures.Taking into account three characteristic t...

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Section: A Magnetic Hamiltonian Of Ybfeomentioning

confidence: 99%

Decoupled spin dynamics in the rare-earth orthoferrite YbFeO3 : Evolution of magnetic excitations through the spin-reorientation transition

Nikitin

Sefat

et al. 2018

Phys. Rev. B

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“…They have suggested that the frustration of the interactions between Fe 3+ and Nd 3+ moments causes the phase competition between the two phases. However, the recently proposed magnetic Hamiltonian based on an inelastic neutron scattering experiment [49] does not identify the ICM structure as the ground state even though the complex network of the interactions was revealed. On the other hand, it has been suggested that the Dzyaloshinskii-Moriya (DM) interaction causes the ICM structure in Ref.…”

Section: Discussionmentioning

confidence: 96%

Magnetic order in the rare-earth ferroborate CeFe3(BO3)4

et al. 2018

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We have studied the magnetic order of the rare-earth ferroborate CeFe3(BO3)4 through the thermodynamic and the neutron diffraction measurements. The heat capacity and the magnetic susceptibility revealed antiferromagnetic magnetic ordering at 29 K. In the neutron powder diffraction data, we observed the magnetic Bragg peaks indexed by the commensurate (CM) propagation vector kCM = (0, 0, 3 2) and the incommensurate (ICM) vector kICM = (0, 0, 3 2 +δ). The incommensurability δ increases with decreasing the temperature, and is evaluated to be 0.04556(16) at 3.7 K. Magnetic structure analysis reveals that the magnetic moments aligning in the ab plane form the collinear antiferromagnetic structure having kCM and helical structure having kICM. Detailed measurements of the magnetic susceptibility exhibit an additional anomaly at 27 K. Furthermore, the temperature dependence of the neutron diffraction profile on the single-crystal sample shows that the ICM and CM ordering occurs at 29 K and 26 K, respectively. These results suggest a phase separation state between the collinear and helical structures. The multiferroicity of CeFe3(BO3)4 is discussed on the basis of the determined magnetic structure.

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“…Spin waves are normally investigated through four experimental methods: spin wave resonance (ferromagnetic resonance) [30][31][32][33][34], inelastic electron scattering (spin-resolved electron energy loss spectroscopy) [35][36][37][38][39], inelastic neutron scattering [40][41][42][43][44][45][46], and inelastic light scattering (Brillouin scattering and Raman scattering) [47][48][49][50][51][52][53][54][55][56][57][58][59][60]. Among these methods, inelastic light scattering would be the most convenient approach for studying spin waves, especially Raman scattering spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Anomalous Behaviors of Spin Waves Studied by Inelastic Light Scattering

et al. 2019

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Magnonics, an emerging research field, aims to control and manipulate spin waves in magnetic materials and structures. However, the current understanding of spin waves remains quite limited. This review attempts to provide an overview of the anomalous behaviors of spin waves in various types of magnetic materials observed thus far by inelastic light scattering experiments. The anomalously large asymmetry of anti-Stokes to Stokes intensity ratio, broad linewidth, strong resonance effect, unique polarization selection, and abnormal impurity dependence of spin waves are discussed. In addition, the mechanisms of these anomalous behaviors of spin waves are proposed. spectroscopy is applied for studying vibrational properties of materials. However, due to the anomalous behaviors of spin wave scattering comparing with vibrational scattering, Raman spectroscopy study of spin wave is difficult and limited. In this paper, we present a review of anomalous behaviors of spin waves observed by inelastic light scattering experiments, especially by Raman spectroscopy. The large asymmetry of anti-Stokes to Stokes intensity ratio, broad linewidth, strong resonance effect, unique polarization selection, and abnormal impurity dependence of spin waves are discussed, and a proposed model for the mechanisms of spin flip, spin relaxing, and spin wave scattering is presented for understanding these anomalous behaviors of spin waves. In addition, two magnonic crystal structures are proposed for manipulating spin waves through analyses of the abnormal impurity dependence of spin waves. The review of the anomalous behaviors of spin waves and the proposed models provide the directions for easier experimental study of spin waves by inelastic light scattering, which will be useful for raising the research efforts for investigating spin waves. This is important for the emerging research of magnonics, which has received extensive interests in the modern magnetism research community.

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Spin-wave dynamics and exchange interactions in multiferroic NdFe3(BO3)4 explored by inelastic neutron scattering

Cited by 11 publications

References 34 publications

Decoupled spin dynamics in the rare-earth orthoferrite YbFeO3 : Evolution of magnetic excitations through the spin-reorientation transition

Decoupled spin dynamics in the rare-earth orthoferrite YbFeO3 : Evolution of magnetic excitations through the spin-reorientation transition

Magnetic order in the rare-earth ferroborate CeFe3(BO3)4

Anomalous Behaviors of Spin Waves Studied by Inelastic Light Scattering

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