****Technical Abstract**** The goal of this project is to explore the physical basis for the concurrent magnetic and ferroelectric order that arises in multiferroic materials. The development of multiferroic order in materials is typically very tightly constrained by the symmetry of the lattice, which determines the transformation properties of the magnetic structure and the associated ferroelectric order. However, in low-symmetry crystals, the relative directions of the magnetic and ferroelectric structures are not restricted by symmetry, and expected to be determined only by the microscopic interactions. This project will focus on probing the microscopic interactions in multiferroics by studying the magnetic and ferroelectric order in iron vanadate, which is a low-symmetry material. These studies will use thermodynamic, magnetic, and electrical techniques to characterize the properties of iron vanadate samples, specifically the details of the magnetoelectric coupling. The microscopic interactions will be tuned by substitutional doping. This project will support the education and training of a PhD student, along with a number of undergraduate and high school studies. These students will be trained in a range of materials science techniques, including sample preparation, and sample characterization at low temperatures. Beyond the specialized training for these students, this project also included outreach efforts to introduce area high school students to current physics research topics as well as contributions to the development of a new Master's program in materials science.
Materials having magnetic properties, such has conventional disk drives, and materials having electrical properties, such as transistors, both have integral roles in modern electronic devices. Recently, researchers have identified a new class of materials that have both magnetic properties and a special kind of electrical property called ferroelectricity. These materials, called multiferroics, offer the potential for developing entirely new types of electronic devices, like magnetic storage that can be controlled using voltage pulses, or non-volatile computer memory that will maintain information even with the power switched off. This project will investigate how these simultaneous magnetic and electrical properties develop in a specific iron-based multiferroic. This will be accomplished using thermodynamic, magnetic, and electrical measurements, all at very low temperatures, with additional detail on the magnetic properties provided by neutron scattering studies. This project will clarify how these joint magnetic and electrical properties can be controlled, with the goal of eventually designing materials that can be incorporated into consumer devices. Along with furthering our basic understanding of these multiferroic materials, this project will provide important training for students. One PhD graduate student, three undergraduate students, and three high school students will learn about preparing materials and electrical and magnetic studies at low temperature. This project will provide a strong background for these students as they prepare for careers in advanced scientific research and technology development.
