Specific heat of the spin density wave state in Ce(Ru0.85Rh0.15)2Si2 under pressure

We have investigated the pressure effect on the magnetic state of the heavy-fermion compound Ce(Ru0.85Rh0.15)(2)Si-2 in which the spin density wave (SDW) is formed below 5.5 K at ambient pressure. The study was carried out by means of measurements of the specific heat up to 1.6 GPa between 0.7 and 10 K for a polycrystalline sample. In the low pressure region below 0.6 GPa, the Neel temperature T-N and the Sommerfeld coefficient gamma show a slight decrease from 5.5 to 4.9 K and from 310 to 290 mJ/K-2 mol, respectively. At higher pressure the peak in the specific heat becomes broad but T-N remains above 5 K, while gamma rapidly decreases. As a possible origin for the observed pressure dependence of T-N and gamma across 0.6 GPa, we propose the change in the SDW state at higher pressure. (C) 1999 Elsevier Science Ltd. All rights reserved.