AVS 61st International Symposium & Exhibition
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI+MG-TuA

Paper MI+MG-TuA10
Current Topics in Magnetism: The Importance of Interfaces

Tuesday, November 11, 2014, 5:20 pm, Room 311

Session: Development of Multiferroic Materials (2:20- 5:00PM) MIND Panel Discussion (5:00-6:30 pm)
Presenter: Mark Stiles, National Institute of Standards and Technology
Correspondent: Click to Email
Interfaces play a crucial role in many magnetic systems. As magnetoelectronic devices shrink, this role is becoming more and more important. Unfortunately, many times these interfaces are not well enough characterized to allow measurements to constrain physical models of the behavior in these systems. In this talk, I give several examples from my own experience of systems of both historical and current interest in which the interfaces play a dominant role but for which very little is known. A historical example is exchange bias, the study of systems in which the behavior of a ferromagnetic film is modified by coupling to it to an antiferromagnet. In spite of decades of study on a wide variety of systems, structural characterization of the interfaces has only been done several times on model systems, despite the fact that all of the coupling occurs at this interface. A topic of recent interest is the study of current induced torques in magnetic bilayers consisting of ferromagnetic thin films coupled to non-magnetic materials with strong spin-orbit coupling. The spin orbit coupling dramatically affects the current induced torques in these systems. An outstanding question is what role the interfacial spin-orbit coupling plays. This can be addressed theoretically by first-principles calculations, but these necessarily assume ideal interfaces between perfectly coherent lattices for material pairs with lattice mismatch on the order of ten percent. Without real characterization of the structure of these interfaces, it is almost impossible to definitively determine which parts of the system are playing important roles. Both of these topics are useful or potentially useful for applications, a characteristic that tends to drive research focused on achieving dramatic results rather than doing the time intensive work necessary to characterize the samples adequately to support a deeper understanding of the underlying physics.