CAREER: Optical Spectroscopy of the Soft-Modes in Multiferroic Single Crystals

*****NON-TECHNICAL ABSTRACT*****

This Faculty Early Career Award at New Jersey Institute of Technology (NJIT) focuses on integrating fundamental studies of multiferroics with the education of students at different levels. Multiferroics belong to a novel class of oxide materials, whose magnetic and electrical properties are interconnected and can influence each other at low temperatures. Recently these materials have attracted great interest within the condensed-matter community and beyond due to the recognized potentials of multiferroics for future multifunctional device applications including magnetically recorded computer memory, optical switches for communication, and mechanical actuators. A comprehensive theory of the mechanisms for multiferroic effects is still under development. The proposed experimental studies of the related atomic vibrations will contribute to an increased understanding of these effects. The studies will also help in the search for new multiferroics that may lead to future devices that can operate in weaker magnetic fields and at higher temperatures. A diverse curriculum will be developed to promote the integration of modern materials research and education. Several Physics courses at NJIT, e.g. 'Fundamental of Spectroscopy' and 'Advanced Physics Laboratory', are to be directly associated with the proposed research. A comprehensive online course of Introductory Physics will be created for freshman students and will be used in outreach programs to local high-school students.

*****TECHNICAL ABSTRACT*****

This Faculty Early Career Award at New Jersey Institute of Technology (NJIT) focuses on the integration of fundamental optical spectroscopy of the soft modes in multiferroic materials with education of students at different levels. Multiferroic magnetoelectrics belong to a novel class of ferroic oxides, whose magnetization and electrical polarization are closely coupled and can influence each other. By applying an electric field one can change the magnetization M in these crystals, while an external magnetic field affects the polarization P. A theoretical understanding of the P-M coupling at the crystal lattice level does not currently exist. The proposed experiments will use far-infrared spectroscopy at the National Synchrotron Light Source and Raman scattering, both in a magnetic field, to focus on this issue. The major research goal is to relate the interplay between anomalies in the dielectric function and magnetization of multiferroic single crystals to the behavior of the soft mode phonons, magnons, and crystal-field infrared-active excitations. Collaboration with National synchrotron radiation facilities is a key part of this project. Several Physics courses will be directly associated with the proposed research: 'Fundamental of Spectroscopy' for graduate students and 'Advanced Physics Laboratory' for fourth-year undergraduates. A comprehensive online course of Introductory Physics as well as a web-based interactive tool 'Prepare for the Coming Quiz' will be created for freshman students and will be used in outreach programs to local high-school students.