At NAME Lab, our research spans a wide spectrum of topics in magnetics and electronics. Our current focus areas include thin-film growth, nanofabrication, spintronics, magnetization dynamics, and topological phenomena. Our goal is to develop novel materials, explore new physics, and unlock their potential for future microelectronics, computing, and communication technologies.

Thin-Film Growth and Nanofabrication

We develop thin-film materials using in-house techniques such as magnetron sputtering, pulsed laser deposition, and liquid phase epitaxy.  Our current focuses are on the growth of magnetic thin films, thin-film topological materials, and their heterostructures. 

Our recent efforts in magnetic thin films include the development of nanometer-thick yttrium iron garnet (YIG) films with ultralow damping, as well as YIG films exhibiting both low damping and perpendicular magnetic anisotropy. These low-damping YIG films serve as an excellent material platform for exploring magnons as information carriers, enabling energy-efficient computing, quantum transduction, and quantum entanglement. Additionally, we work with hexagonal ferrite thin films that exhibit strong magnetic anisotropy, which can be utilized to fabricate microwave and mm-wave resonators and filters for advanced communication systems.

In the realm of topological materials, we employ sputtering techniques to grow thin-film topological Dirac semimetals, Weyl semimetals, and topological insulators. Our investigations focus on studying the topological surface states within these thin films and exploring their potential applications in efficient electric control of magnetism.

For some of our fundamental and applied studies, we need to pattern the aforementioned thin films into nanostructures. To achieve this, we utilize e-beam lithography and focused ion milling techniques.

Spintronics

Spintronics is a dynamic research field that delves into the intrinsic spin properties of electrons. Different from conventional electronics, which predominantly rely on charge-based characteristics, spintronics harnesses both the charge and spin aspects of electrons.  Its impact extends across various technological domains that include magnetic hard disk drives and magnetic random-access memory (MRAM).  It is expected that spintronics will also make critical contributions to quantum computing, neuromorphic computing, and medical sensing and imaging technologies.

At NAME Lab, we study spintronic phenomena in heavy metals, topological materials, magnetic materials, and their heterostructures.  These phenomena include spin Hall effects, spin Seebeck effects, spin pumping, and spin-orbit torque.  Our recent work includes the use of spin currents in a heavy metal, topological insulator, or topological Dirac semimetal thin film to realize efficient electric control of magnetization in a neighboring ferromagnetic thin film.

Magnetization Dynamics

Study on magnetization dynamics is not only of great fundamental interest but is also critical to device applications of magnetic materials.  Our research spans ferromagnetic resonance, spin waves, and magnetization switching dynamics in magnetic thin films.  Specifically, we make use of comprehensive ferromagnetic resonance measurements and numerical analyses to identify major damping mechanisms and quantify contributions to the overall damping constant from different damping processes in magnetic thin films.  These magnetic films include industrial materials for hard disk drive heads and media as well as spin-transfer-torque MRAM from Seagate and Western Digital and materials for medical sensing from Sonera Magnetics.

In the domain of spin waves, our particular focus lies in using nonlinear spin waves to study nonlinear phenomena such as solitons, chaos, and fractals. Additionally, we explore the potential applications of spin waves in quantum transduction, quantum entanglement, and energy-efficient computing.

Topological Phenomena

Topological materials exhibit distinct physical properties that are determined by topology, not by traditional order parameters.  At NAME Lab, we grow thin films of topological insulators, topological Dirac semimetals, and Weyl semimetals via magnetron sputtering.  We study topological surface states in these materials through electric transport and spin pumping experiments; these surface states are not only fundamentally intriguing, but also hold high potential for applications in energy-efficient electronics.  Additionally, we are developing new materials exhibiting topological superconductivity and novel structures hosting topological magnon edge modes.