Roman Verba PhD Senior research scientist Department of physics of mezo- and nanocrystalline magnetic structures (03) Contact Information: Institute of Magnetism 03142 Acad. Vernadskogo 36-b blvd, Kyiv, Ukraine  e-mail: rvv at imag.kiev.ua tel .: +380 44 424 10 20 fax:  +380 44 424 10 20

Research interests

• spin waves, magnonics
• microwave magnetization dynamics
• magnetic nanostructures
• spin-torque oscillators
• voltage-controlled magnetic anisotropy

Main results

• A method of fast switching of magnetization configuration of magnetic nanodot arrays by application of nanosecond field pulses is proposed; the theory of the magnetization switching process is developed.
• Conditions of spin-wave nonreciprocity in arrays of dipolarly coupled magnetic nanodots and nanowires are derived.
• Methods of excitation, amplitude and phase control, stabilization of amplitude and phase of spin waves, propagating in ferromagnetic nanowires, by means of voltage-controlled magnetic anisotropy are proposed and investigated.

Selected publications
1. Q. Wang, P. Pirro, R. Verba, A. Slavin, B. Hillebrands, A. V. Chumak, Reconfigurable nanoscale spin-wave directional coupler, Sci. Adv. 4, e1701517 (2018). 
2. Y.-J. Chen, H. K. Lee, R. Verba, J. A. Katine, I. Barsukov, V. Tiberkevich, J. Q. Xiao, A. N. Slavin and I. N. Krivorotov, Parametric resonance of magnetization excited by electric field, Nano Lett. 17, 572 (2017). 
3. A. Giordano, R. Verba, R. Zivieri, A. Laudani, V. Puliafito, G. Gubbiotti, R. Tomasello, G. Siracusano, B. Azzerboni, M. Carpentieri, A. Slavin, G. Finocchio, Spin-Hall nano-oscillator with oblique magnetization and Dzyaloshinskii-Moriya interaction as generator of skyrmions and nonreciprocal spin-waves, Sci. Rep. 6, 36020 (2016). 
4. L. Yang, R. Verba, V. Tiberkevich, T. Schneider, A. Smith, Z. Duan, B. Youngblood, K. Lenz, J. Lindner, A. N. Slavin, I. N. Krivorotov, Reduction of phase noise in nanowire spin orbit torque oscillators, Sci. Rep. 5, 16942 (2015). 
5. R. Verba, V. Tiberkevich, I. Krivorotov, A. Slavin Parametric excitation of spin waves by voltage-controlled magnetic anisotropy, Phys. Rev. Appl. 1, 044006 (2014). 
6. R. Verba, V. Tiberkevich, E. Bankowski, T. Meitzler, G. Melkov, A. Slavin Conditions for the spin wave nonreciprocity in an array of dipolarly coupled magnetic nanopillars, Appl. Phys. Lett. 103, 082407 (2013).  
7. R. Verba, G. Melkov, V. Tiberkevich, and A. Slavin Collective spin-wave excitations in a two-dimensional array of coupled magnetic nanodots, Phys. Rev. B. 85, 014427 (2012).