Exploration And Physical Property Of The Multifunctional Materials In Heusler Alloys

It can be expected that the Co2TiSb alloy with a Heusler structure is a possiblemagnetic shape memory alloy by first principle calculations.We found that the alloys prepared by arc melting and quenching method are composedof the body-centered cubic Co and Heusler type Co1.22TiSb, and these two phases have asimilar lattice. The phase transition behavior of Co1.25TiSb and the electronic structure ofsuper structure Co-Co1.25TiSb have been investigated, and it exhibited that there is nomartensitic transformation in such alloy. But the Co-Co1.25TiSb with super structure showshigh electron spin polarization, which indicate that high spin polarization can be obtained inthe Co-Co1.25TiSb multilayer materials.The effects of doping elements on structures and martensitic transformation in theCo2TiSb alloy were also studied. We found that after the amount of the replacement withthe main group elements, alloys still able to maintain its martensitic transformationcharacteristics. However, the driving force of phase transition decreases with increasingdoping concentration. The driving force of phase transition increases after doping with Fe,which in favor of phase transition.Co2TiSbxSnx(x=0.25,0.5) samples with pure L21structure were obtained by melt spunmethod. The Co2Ti0.75Fe0.25Sb alloy has been synthesized by melt with a small amount ofthe second phase CoFe, which exhibited a martensitic transformation behavior at250K.