Terahertz magnetoelectric response via electromagnons in magnetic oxides

Kida, N.; Tokura, Y.

doi:10.1016/j.jmmm.2012.02.078

Cited by 11 publications

(9 citation statements)

References 42 publications

(86 reference statements)

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“…Magnetoelectric (ME) effects in multiferroic (MF) or ferromagnetic (metallic) films have brought remarkable interest since promising technological applications in spintronics and ultrafast electric field control on magnetic data storage are seen as imminent 1 , 2 . Characterization of the relative strength for the ME coupling can be obtained by implementing terahertz spectroscopy in rare earth manganites of the type RMnO 3 (R=Tb, Gd, Dy, Eu:Y) 3 , 4 , 5 , 6 demonstrating that the generated electromagnons (mixed spin-waves and photon states) represent, among others, the signature of the ME effect for an approximate range of frequencies between 10 cm −1 and 40 cm −1 at temperatures where antiferromagnetic resonance modes (AFMR) coexist, or more recently, the key mechanism for controllable magnetochromism in Ba 2 Mg 2 Fe 12 O 22 hexaferrites 7 . The magnetoelectric effect emerges when a magnetic field H can induce a polarization vector P at zero applied electric field (E = 0).…”

Section: Introductionmentioning

confidence: 99%

Optical reflectivity and magnetoelectric effects on resonant plasmon modes in composite metal-multiferroic systems

Vargas‐Hernández

2013

Optics Communications

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The rôle of the magnetoelectric effect upon optical reflectivity is studied by adapting an electrodynamic-based model for a system composed by a 2D metallic film in contact with an extended multiferroic material exhibiting weak ferromagnetism. The well-known Nakayama's boundary condition is reformulated by taking into account the magnetoelectric coupling as well as an externally applied magnetic field B in an arbitrary direction. It is found that the reflectance shows strong fluctuations for incident radiation close to the characteristic antiferromagnetic resonance frequency associated with the multiferroic material in the THz regime. These results were verified for a 10 nm metallic foil by using a finite element method (FEM) and the Rouard's approach, for a wide range of wavelengths (0.1 -5 mm), showing good agreement with respect to Nakayama's outcome, for the particular material BaMnF4.

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Section: Introductionmentioning

confidence: 99%

Optical reflectivity and magnetoelectric effects on resonant plasmon modes in composite metal-multiferroic systems

Vargas‐Hernández

2013

Optics Communications

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“…Intrinsic coupling between the order parameters, e.g., ferromagnetism (FM), ferroelectricity (FE), and/or ferroelasticity (for an overview we refer to Refs. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]), allows for multifunctionality of devices with qualitatively new conceptions [10,[22][23][24][25]. Particulary advantageous is the high sensitivity of some MF compounds to external fields [26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Helical multiferroics for electric field controlled quantum information processing

et al. 2014

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Magnetoelectric coupling in helical multiferroics allows us to steer spin order with electric fields. Here we show theoretically that in a helical multiferroic chain quantum information processing as well as quantum phases are highly sensitive to electric (E) field. Applying E field, the quantum state transfer fidelity can be increased and made directionally dependent. We also show that E field transforms the spin-density-wave/nematic or multipolar phases of a frustrated ferromagnetic spin-1 2 chain in chiral phase with a strong magnetoelectric coupling. We find sharp reorganization of the entanglement spectrum as well as a large enhancement of fidelity susceptibility at Ising quantum phase transition from nematic to chiral states driven by electric field. These findings point to a tool for quantum information with low power consumption.

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“…As mentioned above, the subtlety of quantum engines is related to the internal connection between essentially quantum phenomena such as entanglement and the thermodynamic characteristics of the cycle. In this regard, the choice of the working substance for the operating quantum engine is an important issue [22].Recently, there has been great interest in composite multiferroic (MF) materials that possess coupled ferromagnetic (FM) and ferroelectric (FE) properties [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] (for a review we New J. Phys. 16 (2014) 063018 M Azimi et al 1 while the next-nearest interaction is antiferromagnetic < J 0 2 .…”

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confidence: 99%

Quantum Otto heat engine based on a multiferroic chain working substance

et al. 2014

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We study a quantum Otto engine operating on the basis of a helical spin-1/2 multiferroic chain with strongly coupled magnetic and ferroelectric order parameters. The presence of a finite spin chirality in the working substance enables steering of the cycle by an external electric field that couples to the electric polarization. We observe a direct connection between the chirality, the entanglement and the efficiency of the engine. An electric-field dependent threshold temperature is identified, above which the pair correlations in the system, as quantified by the thermal entanglement, diminish. In contrast to the pair correlations, the collective many-body thermal entanglement is less sensitive to the electric field, and in the high temperature limit converges to a constant value. We also discuss the correlations between the threshold temperature of the pair entanglement, the spin chirality and the minimum of the fidelities in relation to the electric and magnetic fields. The efficiency of the quantum Otto cycle shows a saturation plateau with increasing electric field amplitude.Keywords: quantum heat engine, quantum entanglement, frustrated spin chain, multiferroic system IntroductionWith the advances in nanotechnology enabling controlled miniaturization and functionalization of nanostructured materials, questions related to the thermodynamical properties are gaining increased attention. Several theoretical proposals were put forward for nanoscale Brownian motors [1], refrigerators [2] and quantum heat engines [3][4][5][6][7][8][9][10][11][12][13]. On the other hand, for finite systems, the application of the laws of thermodynamics is the subject of an ongoing debate [14]. One of the fundamental questions concerns the size limit to which the working substance might be scaled down. Recent studies point out that the quantum nature of a size-quantized working substance, e.g. a quantum heat engine, may lead to a close connection between the efficiency of the cycle and quantum correlations [15], which can be quantified in terms of the entanglement [16][17][18], behavior that is atypical for classical engines. According to the fundamental laws of thermodynamics, the efficiency of a classical engine is independent of its detail and is solely determined by the character of the cycle itself and the temperatures of the heat baths. The quantum nature of the working substance, however, has key consequences for the engine output power as well. Recently it was shown that purely quantum phenomena, such as noise-induced coherence, yield greater engine output power [19,20].In general, physical phenomena at the cross-over of quantum mechanics and thermodynamics are the subjects of the emergent field of quantum thermodynamics where, among other topics, questions are addressed as to what extent standard classical thermodynamic cycles, such as Carnot or Otto cycles, can be reformulated for quantum systems [4]. A key issue thereby is the difference between thermodynamic and quantum adiabatic processes. For example, a thermodynamical ...

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Terahertz magnetoelectric response via electromagnons in magnetic oxides

Cited by 11 publications

References 42 publications

Optical reflectivity and magnetoelectric effects on resonant plasmon modes in composite metal-multiferroic systems

Optical reflectivity and magnetoelectric effects on resonant plasmon modes in composite metal-multiferroic systems

Helical multiferroics for electric field controlled quantum information processing

Quantum Otto heat engine based on a multiferroic chain working substance

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