Exchange interactions, half metallic ferromagnetism, mechanical, thermal and magneto-electronic properties of full Heusler alloys Co2YGe(Y= Mn, Fe) for acoustical and spintronic devices

The focal point of this article is to pay attention on the half metallic ferromagnetism, structural, elastic, thermal, electronic and magnetic properties of Co2YGe (Y--Mn, Fe) Heusler compounds with Fm-3m crystal structure involving the density functional theory within the framework of full potential linearized augmented plane wave method as integrated in the Wien2k package. The structural optimizations plots confirm that both alloys are in the lower energy state in ferromagnetic order. Moreover the structural parameters are consistent with experiment. The computed elastic properties show the ductile nature of these alloys. Based on the thermal properties of these alloys, Co2MnGe is more favorable for the fabrication of elevated temperature acoustical devices as compared to Co2FeGe. For the calculation of electronic and magnetic properties of Co2YGe (Y--Mn, Fe) alloys in addition to GGA functional, the GGA + U (U= Hubbard parameters) were also adopted. Both alloys are HMF in nature. It is also observed that the values of the compound's magnetic-moments fit excellent with Slater Pauling law. Furthermore we have calculated the formation energy and Curie temperature of these alloys. The negative values of the formation energy of both compounds represent their thermodynamic stability and strong bonding. Higher values of thermal parameters, half metallic nature and ferromagnetism of Co2YGe (Y--Mn, Fe) predict the importance of these compounds in acoustical and spintronic devices respectively.