University of Connecticut

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Condensed Matter Physics Seminar

Monday, February 23, 2015
2:30pm – 3:30pm

Storrs Campus
Gant Science Complex, Room PB-121

Ilya Sochnikov, Department of Applied Physics, Stanford University in Stanford, California

“Magnetic Microscopy of Emergent Phenomena”

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.


Dawn Rawlinson, 486-4916,

Physics Department (primary)

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