Calendar of Events

Oct
18
Wed
Coffee Hour
Oct 18 @ 3:30 pm – 4:15 pm

CEM Faculty, Students and Staff gather weekly for an informal hour of discussion.

 

Oct
25
Wed
Coffee Hour
Oct 25 @ 3:30 pm – 4:15 pm

CEM Faculty, Students and Staff gather weekly for an informal hour of discussion.

 

Nov
1
Wed
Coffee Hour
Nov 1 @ 3:30 pm – 4:15 pm

CEM Faculty, Students and Staff gather weekly for an informal hour of discussion.

 

Nov
11
Sat
Volunteer: Breakfast of Science Champions
Nov 11 @ 9:00 am – 12:00 pm

Volunteers Needed! Comets, craters and computer hard drives, oh my… The CEM and the CCAPP team up as students and teachers from local Columbus schools explore hands-on activities including a super conducting train exhibition, liquid nitrogen demonstrations, nanomagnetism and computer activities, snowballs and explosions in our solar system. Participants begin the morning by having breakfast with scientists and a visit to the planetarium; the rest of the morning is spent engaging in hands-on science activities. (Workshops last approximately 2.5 hours- including breakfast.) Prior to this event, volunteers visited the school to teach an astronomy lesson and following the event, the students returned to OSU for a planetarium visit and a career activity led by CCAPP volunteers.

Contact Michelle McCombs(.75) to volunteer.

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.