Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Magnetismus
MA 15: Spin-Dependent Transport Phenomena II
MA 15.6: Vortrag
Dienstag, 28. März 2006, 11:30–11:45, HSZ 103
Stress vs Coulomb Interaction in La-manganite Films — •Vasily Moshnyaga1, Kai Gehrke1, Oleg Shapoval2, Alexandr Belenciuc2, Bernd Damaschke1, and Konrad Samwer1 — 1I. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen, Germany — 2Institute of Applied Physics, AS RM, str. Academiei 5, MD-2028, Chisinau, Republic of Moldova
La-deficient La(1-δ)MnO(3) (LMO) (δ=0-0.2) films were epitaxially grown on SrTiO(3) (STO) and MgO substrates by metalorganic aerosol deposition technique. The films grown on STO substrate show metal-insulator transition and ferromagnetic ordering for T<Tc=260-285 K, whereas those grown on MgO are insulating and exhibit only weak ferromagnetism for T<100 K. X-ray diffraction reveal a stress-free state of the films grown on MgO with lattice constant c=0.389 nm, which does not depend on *δ*. In contrast the LMO/STO films are biaxially strained and possess c=0.386 nm. Predominant role of Coulomb interaction in the growth of manganite films is elucidated. In the case of MgO substrate the charge compensation leads to the formation of stoichiometric LaMnO(3) phase and second phase of MnO(x). The La-deficiency can be stabilized only by an additional elastic contribution (stress) due to substrate/film lattice misfit. The obtained results open a promising possibility to control the structure and magnetotransport in manganites by the interplay between elastic and Coulomb interaction. SFB 602, TP A2 is acknowledged.