Magnetic, structural and transport properties across the Heusler alloy (Co2FeAl)/n-Si interfacial structure

Abstract

Electronic and magneto-transport studies across the Co 2 FeAl (CFA)/n-Si interfacial structure have been carried out. Magnetic properties of the structure have also been studied from the M-H characteristics and magnetic force microscopy (MFM) features. Surface morphology of the CFA Heusler alloy thin films studied from atomic force microscopy. X-ray diffraction and X-ray photoelectron spectroscopy data of the structure reveals the formation of CFA alloy phase with L2 1 structure along with few silicide phases. MFM data reveals the formation of fine domain structure with average domain size of *17 nm with average magnetic signal strength of 0.19°. Electronic transport (I-V) characteristics shows the large reverse current as compared to forward current which indicates the spin based transport from CFA Heusler alloy side to semiconductor side. I-V characteristics performed in presence of magnetic field shows the magnetic field sensitivity for reverse bias.

X-ray photoelectron spectroscopy (XPS) study of Heusler alloy (Co2FeAl) interfaced with semiconductor (n-Si) structure

“…Such interactions seem to be responsible for the electronic and magnetic properties of layered structures. Our present XPS investigations support our earlier study [1] on Co 2 FeAl/n-Si interfacial structure.…”

“…1) which shows the trace of Si signal which is likely to originate due to interfacial intermixing between Co 2 FeAl alloy and Si substrate. The presence of such iron silicide phases has earlier been observed in our XRD data [1] which is now confirmed by our XPS data. The formation of such silicide phases could also result due to the strong chemical reactivity of n-type Si substrate [21].…”

“…XPS spectra have shown the presence of metallic phases of Fe, Co and Al along with the signal due to Si substrates. Formation of various phases of silicides which were present in the XRD data of Fe/Co was also observed [1] and found to affect the magnetic and transport properties across the junction.…”

“…Hemispherical energy analyzer was used in the fixed analyzer transmission mode with the pass energy (∼40 eV) to give an instrument resolution of ∼0.9 eV. Other details regarding the metallization and XPS measurement have been given in our previous reports [1,8,9].…”