Investigating magnetic and magneto-transport properties of ferromagnetic (FM) structure and antiferromagnetic/ferromagnetic (AFM/FM) heterostructures

Abstract

Electrical transport properties of functional magnetic oxides on the technologically important silicon substrate have been highly investigated in recent years for the spintronic applications. In this study, we probe the magnetic and magneto-transport properties of a hetero-structure of wide band gap semiconducting antiferromagnetic material (α-Fe2O3) and half metallic ferromagnet La0.7Sr0.3MnO3 (LSMO) and compare it with those of the LSMO single layer (thickness ∼60 nm) deposited on Si (100) substrate using pulsed laser deposition technique. X-ray diffraction θ-2θ scan validates the growth of α-Fe2O3 and LSMO phases, with no other impurity or secondary phase. Magnetic studies reveal that LSMO film shows Curie temperature close to 320 K and the bilayer shows the same at 255 K and another anomaly in the bilayer is at 102 K. LSMO single layer shows fairly high negative magnetoresistance (MR%) value of 41% at 214 K; close to MIT (metal-to-insulator temperature) at 230 K, and at 7 T field, which proves it to be potentially good candidate for spin transport across the heterostructure. α-Fe2O3 film shows no MR. Upon integration of α-Fe2O3 with LSMO, positive MR of about 10% is obtained, which stimulates to carry out further probe in spin excitations either optically or at higher magnetic fields across the heterostructures.