The new ternary silicide Gd5CoSi2: Structural, magnetic and magnetocaloric properties

Gd5CoSi2 was prepared by annealing at 1003 K. Its investigation by the X-ray powder diffraction shows that the ternary silicide crystallizes in a tetragonal structure deriving from the Cr5B3-type (I4/mcm space group; a=7.5799(4) and c=13.5091(12) Å as unit cell parameters). The Rietveld refinement shows a mixed occupancy on the (8h) site between Si and Co atoms. Magnetization and specific heat measurements performed on Gd5CoSi2 reveal a ferromagnetic behaviour below TC=168 K. This magnetic ordering is associated to an interesting magnetocaloric effect; the adiabatic temperature change ΔTad is about 3.1 and 5.9 K, respectively, for a magnetic field change of 2 and 4.6 T.