Structural distortions induced during stress relaxation affecting electrical transport of nanometer-thick La0.67(Ba,Ca)0.33MnO3 films
Artikel i vetenskaplig tidskrift, 2010

X-ray diffraction (XRD) and medium-energy ion scattering (MEIS) were used to clarify distortions induced during mechanical stress relaxation in nanometer-thick epitaxial La0.67Ba0.33MnO3 (LBMO) and La0.67Ca0.33MnO3 (LCMO) films fabricated by pulsed laser deposition. It follows from measured XRD and MEIS spectra that LBMO films grown on mismatched LaAlO3 were partly relaxed in the main part of the film, leaving about 4 nm heavily strained portion close to the interface. The critical thickness of LCMO films grown on LaAlO3 substrates was several times larger than that of LBMO due to a better match in lattice parameters. Electro- and magneto-transport parameters of nanometer-thick manganite films grown on mismatched substrates differed markedly from those of LBMO and LCMO layers nucleated and grown on well-matched ones because of non-stoichiometry, biaxial mechanical stresses, and phase separation. The resistivity ρ of manganite films grown coherently at a substrate with small mismatch obeyed the relation ρ=ρ1+ρ2(H)T4.5 at temperatures well below the Curie point. Parameter ρ1 was temperature T and magnetic field H independent while ρ2 was temperature independent but decreased linearly with increasing H.

Mechanical stress

Interface

Distortion of stoichiometry

Heterostructure

Författare

I.T. Serenkov

Ioffe Institute

V.I. Sakharov

Ioffe Institute

Iouri Boikov

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

V. A. Danilov

Ioffe Institute

M. P. Volkov

International Laboratory of High Magnetic Fields Low Temperatures in Wroclaw of the Polish Academy of Sciences

Ioffe Institute

Tord Claeson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Kvantkomponentfysik

Physica B: Condensed Matter

0921-4526 (ISSN)

Vol. 404 5234-5236

Ämneskategorier

Fysik

DOI

10.1016/j.physb.2009.08.286