Date/Time
Date(s) - 04/05/2007
11:00 am - 12:00 pm

Title: MAGNETIC FRUSTRATION: FROM SPIN-SOLIDS TO SPIN-LIQUIDS, GLASSES AND ICES

Speaker: Dr. Oleg Petrenko

Institute: University of Warwick, Coventry

Location: ABB 102

Description:

Magnetic systems often exhibit competing magnetic interactions, that is, interactions that do not all favour the same ordered state. Sufficiently strong competition leads to new physics that is manifested by the appearance of noncollinear or incommensurate ordering, novel critical exponents and rich phase diagrams. In highly frustrated magnetic systems the ground state may remain disordered even at zero temperature. The last two decades have seen a sustained interest in the physics of frustrated magnets both from theoreticians and experimentalists alike.

In this talk I review recent experimental studies of several geometrically frustrated materials performed by the Superconductivity & Magnetism Group at Warwick University. In particular, I describe low-temperature/high-field measurements of magnetisation, specific heat and neutron scattering intensity in the Kagome staircase compounds Ni3V2O8 and Co3V2O8 [1], the triangular lattice magnets (Heisenberg 2D RbFe(MoO4)2 [2] and Ising 1D Ca3Co2O6 [3]) and the members of the titanium pyrochlore oxide family with the general formula R2Ti2O7, where Gd2Ti2O7 [4] may be regarded as an ideal Heisenberg antiferromagnet on a frustrated pyrochlore lattice while Dy2Ti2O7 [5] is considered to be an ideal spin ice material.