Binoy Krishna Hazra

Correlation between structural, magnetic and transport properties of Co2FeSi thin films

Co2FeSi thin films are grown on a Si (1 0 0) substrate using ultrahigh-vacuum magnetron sputtering at different substrate temperatures from 300 °C to 550 °C. The films are characterized using grazing incidence x-ray diffraction, magnetization, and ferromagnetic resonance and temperature-dependent resistivity measurements. The films deposited at 450 °C (TS450) have better magnetic as well as structural properties with the minimum disorder. The temperature dependence of line-width () suggests two-magnon scattering is responsible for the line broadening. The correlation between the disorder and extrinsic broadening of the line-width is brought out clearly for the first time in Co2FeSi thin films. TS450 film has minimum (33 Oe) and Gilbert damping parameter (α = 0.005) at room temperature making it ideal for spintronic applications.

Large anomalous Hall conductivity and Hall coefficient of Co2FeSi thin films

Temperature dependent resistivity ρ(T) and Hall measurements are carried out on 50 nm Co2FeSi thin film deposited at 450°C prepared by magnetron dc sputtering technique. ρ(T) of this film has been analyzed by taking electron-magnon, electron-phonon and electron-electron scattering processes. Large anomalous Hall conductivity and large anomalous Hall coefficient values than those of single crystal are observed. This large value of Hall conductivity suggest that skew scattering is dominant over intrinsic berry phase contribution.

Ferromagnetic resonance study of Co2FeSi thin films

50 nm Co2FeSi thin films were deposited on Si (111) by ultra high vaccum dc magnetron sputtering at different substrate temperatures 300°C, 450°C, 550°C and 600°C. The films are characterized by grazing incidence xrd, magnetic and ferromagnetic resonance measurements. The film deposited at 550°C has B2 crystal structure with high magnetization and low coercivity. Ferromagnetic resonance and magnetic measurements are used as a tool to investigate the homogeneity of Co2FeSi thin films.

Effect of substrate temperature on structure and magnetic properties of Co2FeSi/Si(001) thin films

Co2FeSi thin films were grown onto Si(001) by UHV magnetron sputtering at different substrate temperatures (RT, 300, 400, 450, 500 and 550°C) keeping other sputtering conditions same. The films are disordered at low substrate temperatures and may transform into partially ordered B2 and fully ordered L21 phases upon increasing substrate temperatures. X-ray reflectivity analysis revealed an increase in surface roughness with increase in substrate temperature. The GIXRD measurements confirmed the reflectivity results. The magnetic properties of the prepared Co2FeSi films are investigated and correlated with the structural properties.