Multiferroic materials have the unique multi-functionality of controlling magnetism through electric field and/or electric polarization through magnetic field, which presents possibilities for new technological advances and applications. To fully understand the connection between magnetism and electric polarization, one must have a full understanding of the underlying magnetic ground states within these materials. Through an investigation of the multiferroic material CuFeO2, I examine the effects of anisotropy and magnetic field on the frustrated triangular lattice and determine the magnetic ground states. Through a rotational algorithm of the Holstein-Primakoff expansion for the spin Hamiltonian, the spin-wave dynamics for the multiferroic and high-magnetic-field phases are determined. With the dynamics of the multiferroic phase, I modeled the experimental data of doped CuFeO2. From this detail analysis, it was concluded that the multiferroic ground state is that of a distorted incommensurate spiral, which provides insight into the effects of magnetic frustration within these materials. In closing, I will briefly discuss further research developments on the understanding of interfacial phenomena through magneto-electric coupling, and I will conclude with some future research directions in the pursuit of a full understanding multifunctional materials.
This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Los Alamos National Laboratory (Contract DE-AC52-06NA25396).
Physical Sciences and Mathematics | Physics
Haraldsen , J. T. (2013). Understanding the Magnetic Ground States for Improper Multiferroic Materials. .