Abstract
Electrical resistivity, specific heat, and magnetization measurements on the URuOs
Si
system suggest a phase transition from the ‘hidden order’ phase to another unidentified phase that is likely to be a large moment antiferromagnetic phase. It is noteworthy that the hidden order/large moment antiferromagnetic phase boundary
is enhanced from 17.5 K at
= 0 to 50 K at
= 1. However, as
increases, the gap opening in the Fermi surface due to the hidden order phase transition, deduced from electrical resistivity and specific heat measurements, decreases. This study reveals that both Fe and Os isoelectronic substitutions for Ru in URu
Si
yield an enhancement of
. In contrast to the URu
Fe
Si
system, where the unit cell volume decreases with
, in the URu
Os
Si
system, the unit cell volume increases with
. Thus the enhancement of the hidden order/large moment antiferromagnetic transition temperature cannot be solely due to an increase in chemical pressure.
Acknowledgements
The authors thank C. T. Wolowiec for useful comments on the manuscript.
Notes
Sample synthesis and characterization were funded by the U.S. DOE [grant number DE FG02-04ER46105]. N. Kanchanavatee acknowledges financial support through the Royal Thai Government Scholarship program.