| Autor: |
S P P, Jones, S M, Gaw, K I, Doig, D, Prabhakaran, E M, Hétroy Wheeler, A T, Boothroyd, J, Lloyd-Hughes |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Nature communications. 5 |
| ISSN: |
2041-1723 |
| Popis: |
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 (70 K) and predominantly in rare-earth compounds such as RMnO3. 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. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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