Giant negative thermal expansion in a textured MnCoSi alloy

•Textured stoichiometric MnCoSi alloys were fabricated by slow-cooling thermal treatment.•A giant reversible linear negative thermal expansion as much as 9350 ppm was achieved.•The linear negative thermal expansion of the textured MnCoSi alloy could be up to 70,000 ppm at about 1200 K.•The present MnCoSi alloy demonstrates a stable negative thermal expansion effect under external magnetic field.