The structure, morphology, and electrical properties of epitaxial a -axis-oriented thin films of Nd0.2Sr0.8MnO3 are reported for thicknesses of 10 nm≤t≤150 nm. Films were grown with both tensile and compressive strain on various substrates. It is found that the elongated crystallographic c -axes of the films remain fully strained to the substrates for all thicknesses in both strain states. Relaxation of the a and b axes is observed for t≳65 nm, with films grown under tensile strain developing uniaxial crack arrays (running along the c axis) due to a highly anisotropic thermal expansion. For the latter films, the room-temperature in-plane electrical resistivity anisotropy, ρb/ρc, increases approximately exponentially with increasing film thickness to values of ∼1000 in the thickest films studied. Films under tension have their Ńel temperatures enhanced by ≈25 K independent of thickness, consistent with an enhancement in ferromagnetic exchange along their expanded c axes.
ASJC Scopus subject areas
- Physics and Astronomy(all)