THz ESR study of multiferroic material CuO under pulsed magnetic field

Ohta, H.; Okubo, Susumu; Kobayashi, Tatsuo; Sakurai, Takahiro; Zhang, W.; Yokoyama, Chiori; Zheng, Xu–Guang; Nishihara, Sadafumi; Inoue, Kazuhide; Fujisawa, Masashi; Kikuchi, Hikomitsu; Matsuoka, Eiichi; Sugawara, Hitoshi

doi:10.1109/irmmw-thz.2012.6380174

Cited by 2 publications

(2 citation statements)

References 8 publications

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“…The temperature dependence of the magnon mode energy is reported in Fig. 2(c [48], and THz-TDS (red ×) [21] are also shown. disappears at around 70 K. In comparison, the energy of the observed magnon in CuO was found to decrease as the temperature increased towards T N1 [+ symbols in Fig.…”

Section: Results: Magnonmentioning

confidence: 93%

Influence of nonmagnetic Zn substitution on the lattice and magnetoelectric dynamical properties of the multiferroic material CuO

et al. 2014

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Dynamic magnetoelectric coupling in the improper ferroelectric Cu 1−x Zn x O (x = 0, x = 0.05) was investigated using terahertz time-domain spectroscopy to probe electromagnon and magnon modes. Zinc substitution was found to reduce the antiferromagnetic ordering temperature and widen the multiferroic phase, under the dual influences of spin dilution and a reduction in unit-cell volume. The impact of Zn substitution on lattice dynamics was elucidated by Raman and Fourier-transform spectroscopy, and shell-model calculations. Pronounced softenings of the A u phonons, active along the direction of ferroelectric polarization, occur in the multiferroic state of Cu 1−x Zn x O, and indicate strong spin-phonon coupling. The commensurate antiferromagnetic phase also exhibits spin-phonon coupling, as evidenced by a Raman-active zone-folded acoustic phonon, and spin dilution reduces the spin-phonon coupling coefficient. While the phonon and magnon modes broaden and shift as a result of alloy-induced disorder, the electromagnon is relatively insensitive to Zn substitution, increasing in energy without widening. The results demonstrate that electromagnons and dynamic magnetoelectric coupling can be maintained even in disordered spin systems.

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Section: Results: Magnonmentioning

confidence: 93%

Influence of nonmagnetic Zn substitution on the lattice and magnetoelectric dynamical properties of the multiferroic material CuO

et al. 2014

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“…5c, the magnon frequency increases quadratically with field in the range 0-7 T. This is consistent with high-frequency electron spin resonance (ESR) measurements in fields up to 40 T 49 . The ESR data show additional modes around 300 GHz associated with the collinear phase and the spin-flop transition at 10.2 T 49,50 .…”

Section: Roommentioning

confidence: 88%

High-temperature electromagnons in the magnetically induced multiferroic cupric oxide driven by intersublattice exchange

et al. 2014

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Magnetically induced ferroelectric multiferroics present an exciting new paradigm in the design of multifunctional materials, by intimately coupling magnetic and polar order. Magnetoelectricity creates a novel quasiparticle excitation-the electromagnon-at terahertz frequencies, with spectral signatures that unveil important spin interactions. To date, electromagnons have been discovered at low temperature (o70 K) and predominantly in rare-earth compounds such as RMnO 3 . Here we demonstrate using terahertz time-domain spectroscopy that intersublattice exchange in the improper multiferroic cupric oxide (CuO) creates electromagnons at substantially elevated temperatures (213-230 K). Dynamic magnetoelectric coupling can therefore be achieved in materials, such as CuO, that exhibit minimal static cross-coupling. The electromagnon strength and energy track the static polarization, highlighting the importance of the underlying cycloidal spin structure. Polarized neutron scattering and terahertz spectroscopy identify a magnon in the antiferromagnetic ground state, with a temperature dependence that suggests a significant role for biquadratic exchange.

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THz ESR study of multiferroic material CuO under pulsed magnetic field

Cited by 2 publications

References 8 publications

Influence of nonmagnetic Zn substitution on the lattice and magnetoelectric dynamical properties of the multiferroic material CuO

Influence of nonmagnetic Zn substitution on the lattice and magnetoelectric dynamical properties of the multiferroic material CuO

High-temperature electromagnons in the magnetically induced multiferroic cupric oxide driven by intersublattice exchange

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