CAREER: Probing the Nature of Coupled Ground States in Single Crystals of Magnetoelectric Perovskite Oxides

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

This Faculty Early Career Award supports a project to synthesize and study a new class of materials called magnetoelectric multiferroics.. These materials may find future applications in spin-based electronic devices. In addition, with their nearby electric and magnetic dipole resonances in the frequency domain magnetoelectrics have the potential for realizing intrinsic far-infrared negative index materials (NIM). New magnetoelectric materials will be grown from a floating zone as bulk single crystals and in other forms. Lattice, magnetic, and, electronic structure as well as magnetic properties will be studied over a wide temperature range from ultra-low temperatures to above room temperature using an array of probes, some being accessed through collaborations. These include x-ray diffractometry, magnetometry, ultrasonic propagation and neutron diffraction. These studies will lead to the elucidation of detailed electronic phase diagrams. Additional studies at national synchrotron facilities will be undertaken to increase our understanding of the existence of magnetism in these highly insulating compounds. Charge and spin dynamics at femtosecond time scales will be studied using ultrafast time-resolved MOKE and Raman techniques. A new integrated curriculum in Solid State Physics will be implemented using an innovative laboratory, and students from this course will later obtain internships at local industries. AP Physics teachers from surrounding schools, along with their students, will participate in research activities. Through a partnership with the university's College for Kids program middle and high school students from under-represented groups will be provided stipends to participate in a High School Scholars summer workshop in the Physical Sciences. In addition a program will be created for the Science Bag, a highly popular Friday night magic-show style lecture tradition at the institution, open to the Milwaukee community. %%% A ferroelectric material is generally an electrical insulator that under certain conditions can spontaneously separate its positive and negative charges and thereby develop what is call an "electric dipole moment." This is similar to a bar magnet. However, instead of exhibiting a magnetic field, this "bar" exhibits an electric field. Ferroelectric materials are not usually magnetic. Independently, both magnetic materials and ferroelectric materials find extensive use in modern digital recording media and in memory devices. This Faculty Early Career Award supports a project to investigate new phases of a class of materials called magnetoelectric multiferroics. These materials are found to display both magnetism and ferroelectricity in the same material. Under certain conditions, the application of a voltage could change - or even reverse - the direction of spontaneous magnetization (i.e. an electrical voltage could cause a change in the direction of the magnetic "North pole") in the crystal. The magnetization of a material depends upon a quantity called "spin." Thus these materials may find future applications in electronic devices that depend on the "spin" rather than the electronic charge. New magnetoelectric materials will be grown in bulk single crystals and other forms. These new materials will be studied by a wide variety of experimental techniques elucidate their properties. These studies will deepen the understanding of both magnetism and ferroelectricity. A new integrated curriculum in Solid State Physics will be implemented using an innovative laboratory, and students from this course will later obtain internships at local industries. AP Physics teachers from surrounding schools, along with their students, will participate in research activities. Through a partnership with the university's College for Kids program middle and high school students from under-represented groups will be provided stipends to participate in a High School Scholars summer workshop in the Physical Sciences. In addition a program will be created for the Science Bag, a highly popular Friday night magic-show style lecture tradition at the institution, open to the Milwaukee community.