CME Seminar - Sarah Dunsiger, Munich Technical University - Thursday, June 26th at 11:30am - Smith Seminar Room

[Longbrake, Patricia]

Please join us on Thursday for the CME Seminar presented by Sarah Dunsiger from the Munich Technical University at 11:30am in the Smith Seminar Room.

Spin Excitations on the Pyrochlore Lattice

Geometric magnetic frustration is a ubiquitous phenomenon within condensed matter
physics. "Spin ices" combine the rich phenomenology associated with such competing
interactions with Ising models. Theory predicts the associated low temperature
magnetic excitations consist of deconfined magnetic charges, or monopoles [1,2].
Startlingly, in the archetypal spin ice compounds A2Ti2O7 (A=Dy,Ho), as found in many
highly frustrated magnetic materials, we report spin fluctuations which become
temperature independent at low temperatures [3], behaviour which dominates over any
signature of thermally nucleated monopole excitations.
A major unresolved question concerns the fate of the spin ice state, when the strength
of the local Ising anisotropy is reduced, which may boost the relative importance of
quantum fluctuations [4]. I set our recent investigations using the complementary
techniques of μSR and dc-magnetisation in context, exploring the phase diagram of
these unusual magnetic systems.
[1] I. Ryzhkin, Journal of Experimental and Theoretical Physics 101, 481 (2005).
[2] C. Castelnovo, R. Moessner, and S. L. Sondhi, Nature 451, 42 (2008).
[3] S. R. Dunsiger et al, Physical Review

Thank you,
Trisch

[The Ohio State University]
Trisch Longbrake
Administrative Associate I
Department of Physics Condensed Matter
2196 Physics Research Building, 191 W. Woodruff Ave., Columbus, OH 43210
614-292-2778 Office / 614-292-7557 Fax
longbrake.6 at osu.edu<mailto:longbrake.6 at osu.edu> osu.edu<http://osu.edu/>

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