Ferromagnetic Heusler alloys have the imminent applications in spintronic devices and smart materials. Ferromagnetic materials such as Fe, Co, Ni has a spin polarization about 35-40% but Heusler alloys have 100% spin polarization. The advantages of using these alloys are, they have half metallic property, 100% spin polarization at Fermi level, high Curie temperature etc and these alloys can be used for sensors, actuators, and memory storage devices. Heusler alloys are among the largest families of intermetallic compounds with face centered cubic structure. These alloys are divided into Full, half, inverse, quaternary Heusler alloys depending upon their crystal structure.