Magnetic Microscopy of Emergent Phenomena
| Date/Time: | Tuesday, 10 Feb 2015 from 4:10 pm to 5:00 pm |
|---|---|
| Location: | Physics 0005 |
| Phone: | 515-294-5441 |
| Channel: | College of Liberal Arts and Sciences |
| Actions: | Download iCal/vCal | Email Reminder |
Abstract: Scanning Superconducting QUantum Interference Device (SQUID) microscopy is a versatile technique that is efficiently used to study various emergent phenomena, such as two-dimensional superconductivity, magnetism in complex oxides, bio-magnetism, and protected normal- and super-currents in topological insulators. Following an introduction, I will focus on an intriguing phenomena of magnetic fluctuations in a so-called 'spin-ice' material.
Spin-ices are frustrated magnets that are predicted to host magnetic monopoles, emergent quasiparticles with a net magnetic charge. Previous observations ascribed to the emergent monopoles include spectacular neutron scattering maps and unusual magnetic relaxation behavior. Using SQUID microscopy, we image spontaneous magnetic fluctuations in the spin-ice Ho2Ti2O7. The temperature and frequency dependence of the fluctuations reveal a distribution of activation energies. I will discuss an agreement of the extracted energy distributions with the expected ones for monopole excitations. This work opens new horizons for future studies of emergent phenomena in various classical and quantum magnets.
Bio: Dr. Ilya Sochnikov is a postdoctoral researcher in the Department of Applied Physics at Stanford University, and is affiliated with the Center for Probing the Nanoscale (CPN), and Geballe Laboratory for Advanced Materials (GLAM). His postdoctoral research focuses on mesoscale imaging of superconductors, topological insulators, and magnetic materials. Ilya completed his Ph.D. at Bar-Ilan University in the Department of Physics and Bar-Ilan's Institute for Nanotechnology and Advanced Materials (BINA). His Ph.D. research of nanoscale high temperature superconductors was done in partnership with scientists from Brookhaven National Laboratory. His current and future interests, besides the core ones in strongly correlated materials, include development of fast magnetic and spectroscopic imaging techniques, magnetic imaging techniques for biological systems, and methods for combinatorial studies of materials.