Study of half metallic ferromagnetism and, transport properties of Cd_0.875TM_0.125O (TM = Mn, Fe, Co, Ni) alloys for spintronic applications

In the present work, theoretical investigations of structural, electronic, magnetic, and thermoelectric properties of Cd_0.875TM_0.125O (TM = Mn, Fe, Co, Ni) half-metallic ferromagnets are done using WIEN2K code. The computed results when compared with the reported theoretical works reveal consistency. The band structures for spin up (↑), and spin down (↓) channels reveal the half metallic (Mn, Co, Fe), and frustrated (Ni) magnetism. The nature of magnetism has been analyzed in terms of hybridization among 3d states of TMs, individual Cd (5s, 4d) states, and O (2p) states. The control and function of the electron spin are revealed by calculating exchange energies (Δ_x(d), Δ_x(pd)), crystal field energy (ΔE_cryst) and exchange constant (N_oα, N_oβ), those play a very crucial role in understanding the magnetic nature. Moreover, double exchange and RKKY models are discussed to justify the observed half-metallic, and metallic behaviors, which are responsible for the magnetic moments to stabilize a magnetic polarization. The influence of electron spin is explained using the computed electrical and thermal conductivities, while thermoelectric power is elaborated by computing Seebeck coefficient and power factor.