Nanostructured double perovskite magnetic thin films by PLD

Abstract

Semi-metallic ferromagnetic oxides, having a double perovskite structure, exhibit a variety of strange magneto transport and magnetic characteristics for spintronics applications. The double perovskites Sr2FeMoO6 (SFMO) and Sr2FeWO6 (SFWO) are known as potential magneto resistive materials that exhibit appreciable tunnel-type intrinsic magnetoresistance (TMR) at room temperature. Current research is focused on the deposition and characterization of nanocrystalline thin layers of SFMO and SFWO materials on LaAlO3 substrate with a temperature of 825 °C and pressure of 0.03 mTorr using the pulsed laser deposition (PLD) method. Films are nearly single-crystalline with a predominant c-axis orientation. A smaller peak corresponding to the plane (101) at 2θ = 19.6° was also found, indicating the arrangement of Fe, and Mo ions at B and B' locations in samples. Atomic Force Microscope (AFM) studies reflect uniform grain growth with surface roughness and average grain size of approximately 8 nm and 52.6 nm; 6 nm and 28.2 nm, respectively for SFMO and SFWO thin films. Magnetization measurement at 5 K shows that SFMO is ferromagnetic and SFWO is antiferromagnetic with a significant difference in their magnetic moments. M−T curve of the SFWO film shows a peak at 36.7 K, resembling the Neel temperature. While the M−T graph of SFMO thin films reveals that ferromagnetic transition temperature (Tc) is higher than 320 K.