Sr2FeMoO6+x:film structure dependence upon substrate type and film thickness

The effect of film thickness on the magnetic and magneto-transport properties of Sr2FeMoO6thin films

“…Fix et al [22,23] have obtained pseudomorphic epitaxial growth in SFMO films on STO substrate when the film thickness is less than 50 nm and fully relaxed films when the thickness is larger than 80 nm. Our earlier results [5] and results from Boucher et al [21], however, do not show pseudomorphic growth nor fully relaxed film even at thicknesses over 100 nm. One of the problems that needs to be solved before fabrication of SFMO based multilayer structures, is to improve T C and other magnetic properties that are reduced from bulk samples and at the same time not compromising the surface roughness.…”

“…It has been found that the temperature dependence of resistivity in SFMO films grown on STO changes dramatically when the film thickness is under 66 nm and when the thickness is over 120 nm the typical low temperature upturn is seen in resistivity behaviour [20]. Also the surface roughness increases with increasing thickness [21].…”

Challenges in Sr2FeMoO6−δ Thin Film Deposition

“…It is usually expanded with respect to bulk value regardless of the sign of lattice mismatch of the substrate and decreases toward the bulk value with increasing growth temperature and decreasing deposition rate . With the increase of film thickness, strain in the SFMO thin film becomes relaxed toward the bulk lattice parameter values . A general trend in SFMO films is that the smaller the lattice parameter, the better the magnetic film properties .…”

“…Another effective mechanism for the relief of compressive strain is the formation of secondary phase, e.g., SrMoO 3 , allowing the SFMO film lattice parameters to more closely approach those of bulk SFMO. A mechanism for the relaxation of tensile strain is the formation of a Fe‐rich layer at the substrate/film interface . Octahedra rotation is an additional mechanism for the compensation of both tensile and compressive in‐plane biaxial strain .…”

“…[96] With the increase of film thickness, strain in the SFMO thin film becomes relaxed toward the bulk lattice parameter values. [96,102,105] A general trend in SFMO films is that the smaller the lattice parameter, the better the magnetic film properties. [104] Strain relaxation of SFMO thin films on SrTiO 3 (001) occurs in the range of 30-80 nm.…”