119Sn 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 P 6 3 m c , 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 ( C mag ) was obtained by subtracting the lattice part of heat capacity ( C lat ) obtained from the isostructural non-magnetic stannides Y TSn (T=Cu,Ag). C mag 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 ( C mag ) for RE=Dy and Er exhibits non- T 3 behaviour at low temperatures.