Zhou H D, Wiebe C R, Jo Y-J, Balicas L, Urbano R R, Lumata L L, Brooks J S, Kuhns P L, Reyes A P, Qiu Y, Copley J R D, Gardner J S
Department of Physics, Florida State University, Tallahassee, Florida 32306-3016, USA.
Phys Rev Lett. 2009 Feb 13;102(6):067203. doi: 10.1103/PhysRevLett.102.067203. Epub 2009 Feb 10.
The 2D kagome system Pr3Ga5SiO14 has been previously identified as a spin-liquid candidate in zero field, displaying no magnetic long-ranged order down to at least 35 mK. Perturbations upon such systems, either under applied fields or applied pressure, should induce a spin freezing phase transition, but there are very few experimental realizations of this phenomena other than the well-studied 3D pyrochlore Tb2Ti2O7. In this Letter, we report the observation of a spin freezing phase transition in Pr3Ga5SiO14 through the application of chemical pressure--that is, through a systematic substitution on the Si site with larger ions and an elongation of the nearest-neighbor Pr-Pr distance in the kagome lattice. This results in a suppression of the T2 component of the heat capacity, and the reduction of the exchange constant eventually leads to dipolar-driven spin freezing.
