Abstract
We report ac susceptibility, specific heat, and neutron scattering measurements on a dipolar-coupled antiferromagnet . For the thermal transition, the order-parameter critical exponent is found to be 0.20(1) and the specific-heat critical exponent . The exponents agree with the 2D universality class despite the lack of apparent two-dimensionality in the structure. The order-parameter exponent for the quantum phase transitions is found to be 0.35(1) corresponding to . These results are in line with those found for which has the same crystal structure, but largely different , crystal field environment and hyperfine interactions. Our results therefore experimentally establish that the dimensional reduction is universal to quantum dipolar antiferromagnets on a distorted diamond lattice.
- Received 13 January 2016
DOI:https://doi.org/10.1103/PhysRevLett.116.197202
© 2016 American Physical Society