Low-temperature specific heat of Ce(Ru1-xRhx)2Si2 and (Ce1-xLax)Ru2Si2

Abstract We have measured the specific heat by a thermal relaxation method on about 10 mg single crystalline samples of Ce(Ru 1- x Rh x ) 2 Si 2 ( x =0.1, 0.15, 0.3 and 0.4) and (Ce 0.87 La 0.13 )Ru 2 Si 2 from 1.5 K to 20 K. Ce(Ru 1- x Rh x ) 2 Si 2 with x =0.1 and 0.15 and (Ce 0.87 La 0.13 )Ru 2 Si 2 show magnetic phase transition and the temperature dependence of the magnetic specific heat, C mag , obeys approximately the power law C mag = AT n below the ordering temperatures with n =1.4 for both the Ce(Ru 1- x Rh x ) 2 Si 2 and with n =1.1 for (Ce 1- x La x )Ru 2 Si 2 . The estimated electronic specific heat coefficient γ for x =0.1 is nearly of the same value (= 360 mJ/mol K 2 ) as for CeRu 2 Si 2 . The C mag / T for both x =0.3 and 0.4 diverges logarithmically for T → 0, which suggests the so-called non-Fermi liquid behavior.