Recent developments in the capability to design and fabricate thin films have led to a new degree of control over materials combining desirable magnetic and electronic properties. These multiferroic materials have both long-range magnetic and electrical order and allow the two phenomena to interact. The promise of multiferroics lies in the possibility that combining both magnetism and electrical order can result in new electronic and photonic devices. The work funded by this grant is based on new experimental probes for magnetism in multiferroics that will allow magnetism, structure, and ferroelectricity of to be probed simultaneously. These probes are based on x-ray microscopy and diffraction using synchrotron radiation, which allows multiferroic thin films buried beneath electrodes to be studied. Addressing the origin and structure of the magnetism in multiferroic thin films and the interaction of magnetism with electric fields will allow multiferroic to be more fully developed and exploited. Ultimately, the results of this research could lead to sensors, actuators, and magnetic devices based on optimizing the interaction of electrical and magnetic phenomena in thin films. Graduate and undergraduate students will work in part at national facilities with advanced x-ray characterization techniques and work to develop these techniques further.
TECHNICAL DETAILS: The relationship between magnetic order and ferroelectric polarization in multiferroic oxides holds promise as a way to manipulate magnetism with applied electric fields. This grant supports the development of hard x-ray microscopy probes for the magnetism and ferroelectricity of multiferroic oxide thin films under applied electric fields. Resonant magnetic scattering at the Fe K absorption edge will be used to determine what magnetic order exists in multiferroic bismuth iron oxide thin films and how the magnetism evolves in electric fields. The structural specificity of x-ray diffraction will simultaneously allow changes in structure due to piezoelectricity and polarization switching to be addressed. Understanding the magnetism and ferroelectricity of multiferroics will aid in exploiting the potential of bismuth iron oxide and in designing improved materials. The students involved in this project will participate in scientific collaborations with scientists at national synchrotron light facilities. The work will also involve a high degree of participation by undergraduate researchers. All of the participants in this research will conduct outreach activities including developing of demonstrations of the concepts behind resonant scattering.
