Low-Temperature Specific Heat Study of Antiferromagnetic Transition in Ternary Rare-Earth Metal Silicide R5Ir4Si10 (R: Tb, Dy, Ho, Er).

Abstract We investigated antiferromagnetic transitions of R 5 lr 4 Si 10 (R = Tb, Dy, Ho, Er) by measuring the low-temperature specific heat. The antiferromagnetic transition temperature T N is precisely determined. T N is l0.7 K for R = Tb, T N is 5.8 K for R = Dy, T N is 5.1 K for R = Ho and T N is 3.5 K for R = Er, respectively. These results suggest that the antiferromagnetic transition of the ternary rare-earth metal silicide R 5 lr 4 Si 10 is dominated by the exchange interaction between R 3+ ions like as the antiferromagnetic transitions in the ternary rare-earth metal compounds RCu 2 Ge 2 (R = rare-earth metal). In addition, we report the upturn of the specific heat below 1.5 K observed for R = Tb and Ho.