Effect of substitution of In for Co on magnetostructural coupling and magnetocaloric effect in MnCo1-xInxGe compounds

Effect of replacement of Co by In with larger atomic radius but fewer valence numbers on magnetostructural coupling and magnetocaloric effect is studied in MnCo1-xInxGe compounds. The substitution of Co by a small amount of In (1.5%-2%) can shift martensitic transformation T-stru to lower temperature and make it overlap with Curie temperature T-C. As a result, magnetostructural coupling is created and large entropy change (Delta S) takes place. Further increasing In content to x=0.03 leads to decoupling, but the martensitic transition (T-stru similar to 249K) is still close to the magnetic transition (T-c(A) similar to 269 K). As a result, two close Delta S peaks appear. Mechanism related to different large entropy change in the coupled and decoupled samples are discussed. (C) 2014 AIP Publishing LLC.