Coupled dynamics of polarization and magnetization in ferroelectric-magnetic layers

• Applicant: Dr. Alexander Sukhov
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2011 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 188443797

• Final Report Year: 2015

Final Report Abstract

The project is focused on novel materials - two phase multiferroics, exhibiting coupled ferroelectric and ferromagnetic orders. Aiming at developing a numerical method to couple the magnetization dynamics based on the Landau-Lifhitz-Gilbert equation with the polarization dynamics using the Landau-Khalatnikov equation as well as using Monte-Carlo methods, peculiarities of the switching behavior of ferroelectric and ferromagnetic orders were demonstrated depending on the type of the coupling between the orders. In particular, using as a prototype structure an interface of Fe/BaTiO3, where a strong charge-mediated magneto electric coupling has been evidenced, it was shown that though the subsystems are coupled, the ferroelectric subsystem responses to an external time-dependent electric field on the time scale of several picoseconds, whereas the magnetic subsystem requires up to several hundreds of picoseconds to be fully switched. The effect of the strain-mediated coupling was separately inspected for the same interface, where an externally applied time-dependent electric field caused an interfacial stress of the ferroelectric and resulted in a modified anisotropy of the ferromagnet modifying thus the magnetization. Additionally, within the present calculations the effect of ferromagnetic resonance for Fe/BaTiO3-interface was demonstrated to reveal the strength and the symmetry of the magnetoelectric coupling, which was corroborated in a subsequent experiment. The proposed methods clarified the role of thermal fluctuations in two-phase multiferroics and rendered possible a demonstration of multiferroic systems for signal handling processes.

Publications

• ”Influence of magnetoelectric coupling on electric field induced magnetization reversal in a composite unstrained multiferroic chain”, Physical Review B 85, 054401 (2012)
  Horley, Paul P.; Sukhov, Alexander; Jia, Chenglong; Martínez, Eduardo & Berakdar, Jamal
  
• ”Piezoelectric control of the magnetic anisotropy via interface strain coupling in a composite multiferroic chain”, European Physical Letters 99, 17004 (2012)
  Jia, Chenglong; Sukhov, Alexander; Horley, Paul P. & Berakdar, Jamal
  
• ”Dynamics of localized modes in a composite multiferroic chain”, Physical Review Letters 111, 117202 (2013)
  Chotorlishvili, L.; Khomeriki, R.; Sukhov, A.; Ruffo, S. & Berakdar, J.
  
• ”Magnetoelectric coupling in a ferroelectric/ferromagnetic chain revealed by ferromagnetic resonance”, Journal of Applied Physics 113, 013908 (2013)
  Sukhov, A.; Horley, P. P.; Jia, C.-L. & Berakdar, J.
  
• ”Theoretical proposal for the dynamical control of the nonlinear optical repsonse frequency”, Fluctuations and Noise Letters 12, 1350003 (2013)
  CHOTORLISHVILI, L.; SUKHOV, A.; WIMBERGER, S. & BERAKDAR, J.
  
• ”Thermally activated in-plane magnetization rotation induced by spin torque”, Journal of Applied Physics 114, 123906 (2013)
  Chotorlishvili, L.; Toklikishvili, Z.; Sukhov, A.; Horley, P. P.; Dugaev, V. K.; Vieira, V. R.; Trimper, S. & Berakdar, J.
  
• ”Angular dependence of ferromagnetic resonance as indicator of the nature of magnetoelectric coupling in ferromagnetic-ferroelectric heterostructures”, Physical Review B 90, 22428 (2014)
  Sukhov, A.; Jia, C.-L.; Chotorlishvili, L.; Horley, P. P.; Sander, D. & Berakdar, J.
  
• ”Dipole-dipole interaction in arrays of Fe/Fex Oy core/shell nanocubes probed by ferromagnetic resonance”, IEEE Transactions on Magnetics 50, 1301209 (2014)
  Sukhov, Alexander; Horley, Paul P.; Berakdar, Jamal; Terwey, Alexandra; Meckenstock, Ralf & Farle, Michael
  
• ”Finite-size effects on the magnetoelectric coupling in a ferroelectric/ferromagnetic structure revealed by ferromagnetic resonance”, European Physical Journal Web of Conferences 75, 09001 (2014)
  Sukhov, A.; Horley, P.P.; Jia, C.-L.; Chotorlishvili, L. & Berakdar, J.
  
• ”On the superparamagnetic size limit of nanoparticles on a ferroelectric substrate”, Journal of Physics D: Applied Physics 47, 155302 (2014)
  Sukhov, A.; Chotorlishvili, L.; Horley, P. P.; Jia, C.-L.; Mishra, S. K. & Berakdar, J.