Crystal field splitting mechanisms

Newman, D J; Ng, Betty

doi:10.1017/cbo9780511524295.003

Cited by 59 publications

(165 citation statements)

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“…This mechanism was already proposed in HoMn 2 O 5 and Tb 3 Fe 5 O 12 from FIR measurements [30,31]. In order to test the validity of this scenario in ErMnO 3 , the Er 3+ (J=15/2) CF levels were calculated using a point charge model [32,33], taking into account the 7 O 2− closer neighbors of the two Er sites, with screening factors [34], fitted to recover the experimentally identified CF levels. The influence of a magnetic field was also computed to account for the splitting of the CF levels due to the coupling of the Er 4b with the Mn.…”

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confidence: 90%

Magneto- to Electroactive Transmutation of Spin Waves inErMnO3

et al. 2014

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The low energy dynamical properties of the multiferroic hexagonal perovskite ErMnO3 have been studied by inelastic neutron scattering as well as terahertz and far infrared spectroscopies on synchrotron source. From these complementary techniques, we have determined the magnon and crystal field spectra and identified a zone center magnon only excitable by the electric field of an electromagnetic wave. Using comparison with the isostructural YMnO3 compound and crystal field calculations, we propose that this dynamical magnetoelectric process is due to the hybridization of a magnon with an electro-active crystal field transition. The term magnetoelectric (ME) makes reference to a variety of phenomena in which electric dipoles and magnetic moments are mutually linked [1]. ME processes attract a considerable research interest, largely driven by their potential use in future information technologies [1, 2] and, more recently, by their interpretation in terms of exotic magnetic and ME monopoles [3]. A ME process that is particularly striking is the electric-charge dressing of spin-waves that gives rise to electrically active magnons (or electromagnons) [4].This dynamical ME effect has been most clearly demonstrated in multiferroic materials such as Several microscopic mechanisms have been identified behind the ME character of these hybrid excitations. In essence, they all trace back to the specific couplings between spins and the deformable lattice that can produce ferroelectricity. In orthorhombic RMnO 3 , for example, both the so-called inverse Dzyaloshinksii-Moriya and Heisenberg exchange mechanisms contribute to the static polarization [12] and also generate different electromagnons [5]. In hexagonal YMnO 3 , a phonon-magnon anticrossing has been observed revealing that lattice and spins are dynamically coupled in this system too [13,14]. However, the ME nature of this feature was not been proven and, to the best of our knowledge, no electromagnon has been reported so far in the other members of this family of prominent multiferroics [15][16][17]. In thisFIG. 1: Schematic illustration of ErMnO3 crystallographic and magnetic structure in the temperature range T N < T < TN where Mn magnetic moments are ordered at 120 • (a) and Er moments on the 4b site only are polarized in an antiferromagnetic arrangement (b). This multiferroic phase presents an electric polarisation P along the c-axis. The exchange interactions involved in the Mn magnetic order are also shown.Letter, we report on the presence of a new type of ME excitation in the hexagonal ErMnO 3 multiferroic compound. By means of complementary spectroscopic tools and the comparison with hexagonal YMnO 3 , we show evidence of the transmutation of a regular magnon to an electro-active excitation in ErMnO 3 . We ascribe this effect to a distinct hybridization mechanism between Mn 3+ spin-waves and crystal field (CF) excitations of the Er 3+ rare earth.In ErMnO 3 , the ferroelectric state occurs below T c = 833 K with a spontaneous polarization along the c-axis (pola...

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Magneto- to Electroactive Transmutation of Spin Waves inErMnO3

et al. 2014

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“…The present experimental levels were fitted with the standard single-ion Hamiltonian that accounts for free-ion and crystal-field interactions (see [8] for definitions), which was diagonalized within the full 4f 8 configuration basis states: F term, only three out of the twenty free-ion parameters were allowed to freely vary during the fitting procedure: E av (a constant energy term which sets the barycentre for the whole configuration), ζ (the spin-orbit coupling, which splits the 7 F spectroscopic term into seven J manifolds), and F 2 (to adjust the gap separating the 7 F and the 5 D terms). The other free-ion parameters were kept fixed at the literature values for Tb 3+ in LaCl 3 [9].…”

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confidence: 99%

Crystal field fine spectroscopy of trivalent terbium in yttrium aluminum borate single crystals

Baraldi

Buffagni

Capelletti

et al. 2010

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Hermiticy and time-reversal invariance allow only even rank k operators. Since rank k = 0 does not produce any crystal field splitting, only rank k = 2, 4 and 6 are considered for CFP analysis [31]. To fit CFPs to our experimental data requires the calculation of energy levels from an initial estimate of CFPs.…”

Section: Crystal Field Parameter Fittingmentioning

confidence: 99%

“…However, these parameters do not in themselves give a direct insight into the mechanisms of the crystal field splitting [36]. The rank 4 CFPs are dominated by covalency and closely related overlap contributions [31]. The crystal structure of silicon is the same as that of diamond with tetrahedrally coordinated Si atoms with cubic symmetry and O h point group and Fd3m space group with a unit cell dimension of 5.431 Ǻ and an equilibrium distance between Si atoms of 2.352 Ǻ.…”

Section: Interpretation Of Crystal Field Parametersmentioning

confidence: 99%

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Crystal field analysis of Dy and Tm implanted silicon for photonic and quantum technologies

et al. 2014

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Abstract:We report the lattice site and symmetry of optically active Dy 3+ and Tm 3+ implanted Si. Local symmetry was determined by fitting crystal field parameters (CFPs), corresponding to various common symmetries, to the ground state splitting determined by photoluminescence measurements. These CFP values were then used to calculate the splitting of every J manifold. We find that both Dy and Tm ions are in a Si substitution site with local tetragonal symmetry. Knowledge of rare-earth ion symmetry is important in maximising the number of optically active centres and for quantum technology applications where local symmetry can be used to control decoherence. 3854-3856 (1996). 14. J. D. Carey, R. C. Barklie, J. F. Donegan, F. Priolo, G. Franzo, and S. Coffa, "Electron paramagnetic resonance and photoluminescence study of Er-impurity complexes in Si," Phys. Rev. B 59(4), 2773-2782 (1999 391-406 (1966). 24. R. M. Macfarlane, "Photon-echo measurements on the trivalent thulium ion," Opt. Lett. 18(22), 1958-1960 (1993). 25. J. B. Gruber, B. Zandi, and L. Merkle, "Crystal-field splitting of energy levels of rare-earth ions Dy 3+ (4f 9 ) and Yb 3+ (4f 13 ) in M(II) sites in the fluorapatite crystal Sr 5 (PO 4 ) 3 F," J. Appl. Phys. 83, 1009-1017 (1998). 26. U. Walter, "Treating crystal field parameters in lower than cubic symmetries," J. Phys. Chem. Solids 45(4), 401-408 (1984). 27. M. Lourenço, R. Gwilliam, and K. Homewood, "Eye-safe 2 μm luminescence from thulium-doped silicon," Opt. 699-762 (1989). 37. J. J. Baldoví, S. Cardona-Serra, J. M. Clemente-Juan, E. Coronado, A. Gaita-Ariño, and A. Palii, "SIMPRE: A software package to calculate crystal field parameters, energy levels, and magnetic properties on mononuclear lanthanoid complexes based on charge distributions," J. Comput. Chem. 34(22), 1961-1967 (2013). 38. J. J. Baldoví, J. M. Clemente-Juan, E. Coronado, A. Gaita-Ariño, and A. Palii, "An updated version of the computational package SIMPRE that uses the standard conventions for Stevens crystal field parameters," J.

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Crystal field splitting mechanisms

Cited by 59 publications

References 0 publications

Magneto- to Electroactive Transmutation of Spin Waves inErMnO3

Magneto- to Electroactive Transmutation of Spin Waves inErMnO3

Crystal field fine spectroscopy of trivalent terbium in yttrium aluminum borate single crystals

Crystal field analysis of Dy and Tm implanted silicon for photonic and quantum technologies

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