Click here for a printable version of this page.
Condensed Matter Seminars
| Condensed Matter
Thursday, March 17, 2005
Physics Building, Room 204
Note special time.
Note special room.
[Host: Seung-Hun Lee ]
"How to Relax Frustrated Systems: Spin and Orbital Physics in V and Cr Spinels"
Geometrical frustration gives rise to a large number of degenerate ground states and suppresses a simple-minded long-range ordering in general. Here we discuss theoretically how the degeneracy is lifted in three-dimensionally frustrated pyrochlore systems whose lattice structure consists of corner-sharing tetrahedra. The pyrochlore systems are most typically found in the so-called B spinel oxides. Focusing on the spinels
with B=V and Cr, we explore the low-temperature physics by the mean-field argument and Monte Carlo simulation for effective spin-orbital-lattice coupled models.
For V spinels, we clarify the strong interplay between spin and orbital degrees of freedom.
Orbital ordering reduces the magnetic frustration partially and realizes weakly coupled
one-dimensional chains in the three-dimensional pyrochlore lattice. For Cr spinels,
we show that the system exhibits novel phase transitions under the external magnetic
field due to the spin-Peierls type mechanism. An emergence of a half-magnetization
plateau is discussed in detail.
To add a speaker, send an email to
Please include the seminar type (e.g. Condensed Matter Seminars), date, name of the speaker, title of talk, and an abstract (if available).