Calendar of Events

Dr. Brandon Howe (Air Force Research Labs): Next-Generation Frequency-Agile RF/microwave Electronic Materials and Processing Research at AFRL
Apr 11 @ 10:00 am – 11:00 am
Dr. Brandon Howe (Air Force Research Labs): Next-Generation Frequency-Agile RF/microwave Electronic Materials and Processing Research at AFRL @ PRB 1080

Next-generation warfighter electronics rely on the development of truly disruptive and robust electronic and optical materials in order to enable game-changing advancements in RF/microwave performance and frequency-agility. The device community is extremely materials limited with regard to low-loss RF/microwave materials and major scientific challenges lie within the creation of novel materials and heterostructures with exceptionally high crystalline quality in order to unlock and explore unique and interesting electronic and optical properties. In order to accomplish this, one must either make large investments into costly reactors (MBE for instance), or create novel synthesis schemes in order to access never-before-achieved processing space, thus unlocking the ability to grow novel materials with enhanced physical properties. Recently, at the Materials and Manufacturing Directorate at AFRL, we have built up a state-of-the-art PVD epitaxial growth suite capable of quickly synthesizing and scanning through an enlarged processing space in order to rapidly identify novel materials with enhanced physical properties and assessing their potential for AF application. This talk will focus on the buildup and characterization of both a fully automated UHV pulsed laser epitaxy tool for the growth of high quality ferromagnetic, magnetoelectric, and UWBG oxides and heterostructures, as well as a truly one-of-a-kind and fully automated multifunctional epitaxial growth system (MEGS) capable of applying magnetic fields during both magnetron sputter epitaxy as well as pulsed laser deposition and creating complex metal/metal nitride/oxide heterostructures never before achieve. I will show how these systems are already creating exceptionally high quality transition metal nitride for resilient plasmonics (as TiN and ZrN mirror the properties of gold and silver) and novel magnetic oxides with record low-loss magnetic and microwave performance. Single crystal nitrides grown by sputtering demonstrate properties among the best reported while our novel AlNiZnFerrite material demonstrates record high magnetostriction while mitigating prohibitively large losses (microwave damping). I will briefly touch at the end our expanding effort in the prototyping and characterization of novel magnetic and magnetoelectric materials and devices.

Dr. Brandon Howe is a Materials Engineer at Air Force Research Lab’s Materials and Manufacturing Directorate, Nanoelectronic Materials Branch. He was recruited to AFRL under the SMART (Science Mathematics, and Research for Transformation) Scholarship program in 2006. He graduated in 2011 from University of Illinois at Urbana-Champaign, after studying under the guidance of Profs. Ivan Petrov and Joe Greene. During his time there he won several graduate student research awards in the area of Thin Films and Vacuum Technology. He has spent the last five years renovating, redesigning and constructing a UHV PLD and magnetron sputter epitaxy suite, earning him the 2015 Charles J. Cleary Scientific Achievement Award. He is now leading the Epitaxial Magnetoelectrics effort for Next-Generation Tunable RF/Microwave components, recently recognized by AFOSR as one of their top 10% STAR Team efforts.

Physics of Emerging Materials
May 23 – May 25 all-day

The CEM Internal Advisory Council, a grassroots committee of CEM students and postdoctoral researchers, created this workshop to inform the Center’s direction and improve the educational and research experiences of CEM students. POEM will be composed of tutorials by faculty, student talks, poster sessions, and will provide extensive opportunities for interaction between CEM students (on and offsite), and students at NMHU (New Mexico Highlands University), as well as CEM faculty. The workshop also  provides a platform to CEM faculty for exchange of innovative ideas to further the research direction of CEM. This internal workshop is closed to the public.

May 23rd (Tuesday)
9:00-9:45 am:              Meeting with CEM internal advisory council
9:45- 11am:                 CEM Research Overview Poster session
11- Noon:                    Research discussions and optional Research lab tours
Noon- 1:30 pm:          Lunch with PREM and off site students/faculty
1:30- 5:00 pm:            Research discussions and optional Research lab / NSL tours
5:00-5:45 pm:             Welcome speech by Chris
5:45- 6:00 pm:            Poster setup
6:00-7:30 pm:             light refreshments

May 24th (Wednesday)
8:00-8:45 am                 Breakfast
8:45- 9:00 am                Announcements
9:00- 10:30 am              Tutorial 1- Spin-orbit coupling
10:30- 11:00 am            Coffee break
11:00- 11:30 am            Talk
11:30- Noon                  Talk
Noon- 1:30 pm              Lunch
1:30- 3:00 pm                Tutorial 2- Spin thermal transport
3:00-3:30 pm                 Coffee Break and group photo
3:30-4:00 pm                Talk
4:00-4:30 pm                 Talk
4:30-6:30 pm                 Poster Session
6:30-8:00 pm                 Dinner

May 25th (Thursday)
8:00-8:45am                  Breakfast
8:45- 9:00 am                Announcements
9:00- 10:30 am              Tutorial 3- Topology in band structures
10:30- 11:00 am            Coffee break
11:00- 11:30 am            Talk
11:30- Noon                  Talk
Noon- 1:30 pm              Lunch
1:30- 2:00 pm               Talk
2:00- 2:30 pm               Talk
2:30-3:00 pm                Talk
3:00-3:30 pm                Coffee and closing remarks
3:30-4:30 pm                Brainstorming future research directions


IRG-1 Seminar: Dr. Arun Paramekanti, “Magnetism and nematicity in (111) oxide 2D electron gases”
Sep 20 @ 2:00 pm – 3:00 pm

Dr. Arun Paramekanti

Wednesday, September 20th at 2pm in PRB 4138

Magnetism and nematicity in (111) oxide 2D electron gases

Abstract: Recent experiments have begun to explore surface and interface 2D electron gases of (111) oxide heterostructures. Motivated by these experiments, we theoretically examine the many-body instabilities of such 2DEGs driven by multiorbital interactions. We find a rich variety of ferromagnetic and antiferromagnetic orders accompanied by ferroorbital order which breaks lattice rotational symmetry. Such ordered phases or their fluctuating variants might lead to electronic nematicity, which might potentially explain the low temperature onset of transport anisotropies observed in certain experiments.

Alumni Career Series: Morgan Welsh Bernier (JP Morgan Chase)
Sep 28 @ 11:30 am – 12:30 pm
Gleb Kakazei (University of Porto) “Vortices and skyrmions in nanopatterned magnetic structures”
Nov 13 @ 11:00 am – 12:00 pm

Please join the Center for Emergent Materials and Condensed Matter Experiment communities for a special seminar:

Monday, November 13, 11:00AM in PRB 4138
Gleb Kakazei,  IFIMUP-IN/Department of Physics and Astronomy, University of Porto, Porto, Portugal
“Vortices and skyrmions in nanopatterned magnetic structures”

In the first part of the talk our new results on magnetization dynamics of vortex-state circular nanodots with relatively large radius/thickness aspect ratio 0.25 – 0.7 will be presented. They can be summarized as:
1) A number of spin excitation modes were detected using broadband ferromagnetic resonance spectroscopy in the frequency range 0.5-6 GHz. The modes are found to be flexure oscillations of the vortex core string with n = 0,1,2… nodes along the dot thickness, i.e. higher-order gyrotropic modes.
2) It was established that above some thickness the intensity of more complicated n = 1 gyrotropic mode is unexpectedly higher than the one of n = 0 (uniform mode). The observed behavior is explained on the basis of the inhomogeneous vortex mode phase profiles.
3) With increase of dot thickness new azimuthal modes having curled structure at surfaces and radial nodes at dot central plane appear. Such complex structure of modes is a consequence of increasing thickness nonuniformity of effective field. These “curled” modes, in contrast with common uniform along dot thickness azimuthal modes, have a significant difference in the intensity between clockwise and counterclockwise modes of the same type.
In the second part a new route to obtain skyrmions and their arrays in relatively thick (up to 5 nm) continuous films of 3d magnetic metals at room temperature and in the absence of external magnetic fields will be discussed. It is based on the formation of strong vertical stray dipolar fields in the vicinity of film surface. Our micromagnetic simulations and analytical calculations demonstrate that this goal can be achieved by stacking two ferromagnetic subsystems – continuous film with in-plane anisotropy (where skyrmions will be formed) and antidot array with perpendicular anisotropy (stray fields will be created at the hole edges). By adjusting magnetizations and thicknesses of the layers, interlayer exchange coupling strength and hole diameters, different configurations for room temperature magnetic skyrmion arrays were obtained. Also, by introducing non-magnetic layer between two subsystems it is possible to create stable vortex-antivortex pairs with peculiar magnetic properties.