Structure and magnetic properties of LaFe11.5−xCoxSi1.5C0.2 compounds for magnetic refrigeration near room temperature

► Large amount of 1:13 phase was obtained in the ingots. ► Co and C doping can obviously shorten the term of the annealing process. ► Substitution effect of Co on the formation process of 1:13 phase and MCE were studied. ► Large (−ΔS) and ΔTWHH was obtained in LaFe11.5−xCoxSi1.5C0.2 compounds. ► Large, similar entropy changes of two composite were proposed near room temperature.