Calendar of Events

Sep
20
Wed
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.

Sep
28
Thu
Alumni Career Series: Morgan Welsh Bernier (JP Morgan Chase)
Sep 28 @ 11:30 am – 12:30 pm
Nov
13
Mon
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”

Abstract
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.

Jan
25
Thu
Alumni Career Series: Michael Page (Air Force Research Laboratory, Materials and Manufacturing Directorate)
Jan 25 @ 11:30 am – 12:30 pm

Students interested in attending a luncheon with the speaker should contact Rachel Page(.257). Limited to 11 seats.

RSVP: https://osu.az1.qualtrics.com/jfe/form/SV_0ctHS8pApgllzSd

Feb
22
Thu
Alumni Career Series: Richelle Teeling-Smith (Mount Union University)
Feb 22 @ 11:30 am – 12:30 pm

 

Students interested in attending a luncheon with the speaker should contact Rachel Page(.257). Limited to 11 seats.