Field induced ordering in highly frustrated antiferromagnets

Zhitomirsky, M. E.; Honecker, A.; Petrenko, O. A.

Field induced ordering in highly frustrated antiferromagnets

Authors

Zhitomirsky, M. E.

Honecker, A.

Petrenko, O. A.

Description

We predict that an external field can induce a spin order in highly frustrated classical Heisenberg magnets. We find analytically stabilization of collinear states by thermal fluctuations at a one-third of the saturation field for kagome and garnet lattices and at a half of the saturation field for pyrochlore and frustrated square lattices. This effect is studied numerically for the frustrated square-lattice antiferromagnet by Monte Carlo simulations for classical spins and by exact diagonalization for $S=1/2$. The field induced collinear states have a spin gap and produce magnetization plateaus.
4 pages, new analytical proof the order by disorder by thermal fluctuations is added