The ability to switch magnetic states using an electric field has the potential to reduce power consumption for current state-of-the-art memory storage devices by two orders of magnitude. The multi-ferroic material, hexagonal holmium manganite HoMnO3, exhibits giant magneto-elastic coupling and it is an important system in which to test our ideas on how to control magnetic phases using an electric field. In this project we shall study how the electric and magnetic polarizations interact with each other through structural and magnetic excitations.
We have grown single crystals of HoMnO3 suitable for inelastic neutron scattering (INS) experiments using the optical floating-zone technique at Royal Holloway. The student will measure the excitations from HoMnO3 by INS using the LET spectrometer at ISIS. The student will also develop software to separate the magnons and the phonons using XYZ polarization analysis. Finally, the student will determine the magnetic exchange interactions by comparison with simulations using the SpinW code, and calculate the lattice dynamics by first-principles density-functional theory using the CASTEP code.
The PhD project will be located at the ISIS Facility in Oxfordshire, and at Royal Holloway, University of London. Applicants should have a degree in a Physics discipline. Academic knowledge of condensed matter physics will be an advantage. Further information can be obtained from Professor Jon Goff, telephone +44 (0)1784 443485, e-mail [email protected], or Dr David Voneshen, telephone +44 (0)1235 446410, e-mail [email protected].