| AVS 66th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures Division | Wednesday Sessions |
| Session MI+2D-WeM |
| Session: | Emerging Multifunctional Magnetic Materials I and Magnetocaloric Materials |
| Presenter: | Janice Musfeldt, University of Tennessee Knoxville |
| Authors: | J.L. Musfeldt, University of Tennessee Knoxville S. Fan, University of Tennessee Knoxville K.A. Smith, University of Tennessee Knoxville H. Das, Cornell University A.F. Rebola, Cornell University B.S. Holinsworth, University of Tennessee Knoxville J.A. Mundy, University of California at Berkeley C. Brooks, Cornell University M. Holtz, Cornell University R. Ramesh, University of California at Berkeley D.A. Muller, Cornell University D.G. Schlom, Cornell University C.J. Fennie, Cornell University S.A. McGill, National High Magnetic Field Laboratory |
| Correspondent: | Click to Email |
Multiferroics are fascinating materials in which ferroelectric and magnetic orders coexist and spatial inversion and time-reversal symmetries are simultaneously broken. Outstanding challenges that currently prevent widespread application in memory and logic devices as well as neuromorphic computing include requirements for (i) a large coupling coefficient and (ii) room temperature operation. The development of a homologous series of superlattices with formula (LuFeO3)m:(LuFe2O4)n offers a path forward, although questions still exist about the microscopic origin of the high-temperature magnetism and the nature of the charge ordering pattern. In order to resolve these issues and provide additional insight into how external stimuli like magnetic fields can control behavior, we combined optical spectroscopy, magnetic circular dichroism, and first principles calculations to reveal the response of the (LuFeO3)m:(LuFe2O4)n superlattice. Each of the unique iron centers has excitations at slightly different energies, so by analyzing features in the dichroic rotation - which are proportional to net magnetization - and the character of the optical hysteresis loops at these energies, we reveal the magnetic field - temperature (H - T) behavior and how spin in the LuFe2O4 layer is the most significant contributor to the overall magnetic response. We also find that trends in the coercive field can be interpreted in terms of how the exchange strength depends upon the Fe site. The techniques developed here open the door to the microscopic analysis of materials with multiple metal centers and strong charge, spin, orbital, and lattice entanglement.