Effect of the post annealing cooling rate on the martensitic transformation and the magnetocaloric effect in Ni-Mn-Sn ribbons

•Textured polycrystalline ribbons were produced, which undergoes a martensitic transformation near room temperature.•The ribbons were annealed above the ODT and cooled down by three different paths having a decreasing order of the cooling rate.•The atomic ordering, ground state magnetic properties and the characteristics of the martensitic transformation were influenced by the cooling path.•Slow cooling enhanced the relative cooling power of the samples which is beneficial for magnetocaloric applications.