Sn Mössbauer spectroscopy and specific heat studies of the stannides RETSn (RE=Gd-Er and T=Cu,Ag)

The stannides RETSn (RE=Gd-Er and T=Cu,Ag), NdPtSb type structure, space group P6₃mc, have been investigated by ¹¹⁹Sn Mössbauer spectroscopy and specific heat studies. Small transferred magnetic hyperfine fields are detected at the tin nuclei at 4.2 K in the ¹¹⁹Sn Mössbauer spectra of RECuSn (RE=Tb,Dy and Ho) which reveal that these compounds undergo magnetic transitions at low temperatures. Heat capacity (C) measurements show that the title compounds undergo antiferromagnetic ordering. In order to explore the magnetic behaviour below the Néel temperature (T_N), the magnetic part of heat capacity was obtained by subtracting the lattice part of heat capacity obtained from the isostructural non-magnetic stannides Y TSn (T=Cu,Ag). of GdCuSn exhibits an equal moment (EM) magnetic structure and also exhibits multiple transitions below T_N, revealing higher order exchange interactions. Among the REAgSn stannides, the magnetic part of heat capacity for RE=Dy and Er exhibits non-T³ behaviour at low temperatures.