Pyrochlore magnets are candidates for spin-ice behavior. We present theoretical simulations of relevance for the pyrochlore family R2Ti2O7 (R= rare earth) supported by magnetothermal measurements on selected systems. By considering long ranged dipole-dipole as well as short-ranged superexchange interactions we get three distinct behaviours: (i) an ordered doubly degenerate state, (ii) a highly disordered state with a broad transition to paramagnetism, (iii) a partially ordered state with a sharp transition to paramagnetism. Thus these competing interactions can induce behaviour very different from conventional ``spin ice''. Closely corresponding behaviour is seen in the real compounds---in particular Ho2Ti2O7 corresponds to case (iii) which has not been discussed before, rather than (ii) as suggested earlier.
@article{arxiv.cond-mat/9902010,
title = {Ising pyrochlore magnets: Low temperature properties, ice rules and beyond},
author = {R. Siddharthan and B. S. Shastry and A. P. Ramirez and A. Hayashi and R. J. Cava and S. Rosenkranz},
journal= {arXiv preprint arXiv:cond-mat/9902010},
year = {2009}
}
Comments
5 pages revtex, 4 figures; some revisions, additional data, additional co-authors and a changed title. Basic ideas of paper remain the same but those who downloaded the original version are requested to get this more complete version