Abstract
The coexistence of electric polarization and magnetization in multiferroic materials provides great opportunities for realizing magnetoelectric coupling, including electric field control of magnetism, or vice versa, through a strain mediated magnetoelectric interaction effect in layered magnetic/ferroelectric multiferroic heterostructures. Strong magnetoelectric coupling has been the enabling factor for different multiferroic devices, which however has been elusive, particularly at RF/microwave frequencies.In this presentation, I will cover the most recent progress on novel layered microwave multiferroic heterostructures and devices, which exhibit strong magnetoelectric coupling. We will demonstrate strong magnetoelectric coupling in novel microwave multiferroic heterostructures. These multiferroic heterostructures exhibit a giant voltage tunable magnetic field of 3500Oe, and a high electrostatically tunable ferromagnetic resonance frequency range between 1.75~ 7.57 GHz, a tunable frequency of 5.82 GHz or fmax/fmin=4.3. We will show new magnetoelectric sensors based on nano-electromechanical system (NEMS) magnetoelectric resonators, which operate at an electromechical frequency of 215MHz and show an ultra-high sensitivity of 200~300picoTesla at room temperature in unshielded lab environment. These NEMS magnetoelectric sensors represent the most sensitive nanoscale room-temperature magnetic sensors, which is predicted to be able to reach 1~10pT DC magnetic field sensitivity, and will have great impacts on biomagnetic sensing, navigation, aerospace, surveillance, etc. At the same time, we will demonstrate E-field modulation ofanisotropic magnetoresistance, giant magnetoresistance and exchange bias at room temperature indifferent multiferroic heterostructures, multiferroic voltage tunable bandpass filters, voltage tunable inductors, tunable bandstop filters, tunable phase shifters and spintronics.

Short Bio:
Nian Sun is a professor at the Electrical and Computer Engineering Department, Northeastern University. He received his Ph.D. degree from Stanford University. Prior to joining Northeastern University, he was a scientist at IBM and Hitachi Global Storage Technologies. Dr. Sun was the recipient of the NSF CAREER Award, ONR Young Investigator Award, the SørenBuus Outstanding Research Award, etc. His research interests include novel magnetic, ferroelectric and multiferroic materials, devices and subsystems. He has over 150 publications and over 20 patents and patent disclosures. One of his papers was selected as the “Ten most outstanding full papers in the past decade (2001~2010) in Advanced Functional Materials”. Dr. Sun has given over 80 invited or keynote presentations in national and international conferences and universities. He is an editor ofIEEE Transactions on Magnetics, and a fellow of the Institute of Physics, and of the Institution of Engineering and Technology.