The temperature dependence of the thermal expansion coefficient α has been measured in URu2Si2 under uniaxial pressure σ along the  and  directions up to ∼0.6 GPa. For both cases, the hidden-order phase transition temperature T0 increases with increasing uniaxial pressure. An anomaly Δα of the thermal expansion coefficient at T0 appears to be enhanced under a small uniaxial pressure (<0.03 GPa). An antiferromagnetically ordered phase appears at TX above the critical pressure σX∼0.25 GPa for uniaxial pressure along the  direction, whereas no antiferromagnetic transition is detected up to ∼0.6 GPa for uniaxial pressure along the  direction, indicating that the critical pressure is beyond ∼0.6 GPa for the  case. In the previously reported hydrostatic case, an antiferromagnetic phase transition appears above the critical pressure PX∼0.5 GPa. The difference in critical pressure between σX and P X can be understood in terms of the pressure dependence of the U-U distance in the basal (001) plane.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2013 Mar 18|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics