  The all-d-metal Mn2-based Heusler ferromagnetic shape memory alloys
Mn50Ni40-xCoxTi10 (x = 8 and 9.5) are realized. With a generic comparison
between d-metal Ti and main-group elements in lowering the transformation
temperature, the magnetostructural martensitic transformations are established
by further introducing Co to produce local ferromagnetic Mn-Co-Mn
configurations. A 5-fold modulation and (3, -2) stacking of [00 10] of
martensite are determined by XRD and HRTEM analysis. Based on the
transformation, a large magneto-strain of 6900 ppm and a large volume change of
-2.54% are observed in polycrystalline samples, which makes the all-d-metal
magnetic martensitic alloys of interest for magnetic/pressure multi-field
driven applications.
