Magnetocaloric properties of a novel ferromagnet Gd3Co4+xAl12−x (x = 0.50)

• Gd3Co4.5Al11.5 crystallizes with the hexagonal Gd3Ru4Al12 structure-type.
• The magnetic atoms are forming a distorted Kagomé lattice.
• It orders ferromagnetically in a quite extended temperature range below 40 K.
• It presents interesting features for low temperature magnetocaloric cooling.

A novel gadolinium and cobalt based aluminide, namely Gd3Co4+xAl12−x (x = 0.50(3)) is shown to crystallize in the hexagonal Gd3Ru4Al12 structure-type (space-group P63/mmc, a = 8.6830(1) Å, c = 9.3164(2) Å at room temperature). The investigation of its magnetic properties revealed a reversible ferromagnetic ordering at TC ≈ 40 K but expanding in a wide temperature range, potentially due to the geometrical magnetic frustrations expected in this structure-type. The magnetocaloric properties of this intermetallic, determined from both magnetization and specific heat data, are dominated by a maximum entropy variation of −3.28 J kg−1 K−1 at 39(1) K and an adiabatic temperature change of about 1.5 K extending from 20 to 40 K, highlighting some interest for low temperature applications.