Structural studies of annealed ultrathin La0.8MnO3 films

Abstract

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Structural, magnetic, and transport studies of La0.8MnO3 films

“…X-ray absorption measurements reveal significant local distortions occur in the MnO 6 octahedra of the 60 Å film ͑more distorted than LaMnO 3 ) while the differences between the 300 and 1600 Å films are small. The results significantly expand our earlier study of these films 16 and fill in significant details. a͒ Electronic mail: tyson@adm.njit.edu…”

Off-Stoichiometry Effects on the Crystalline and Defect Structure of Hexagonal Manganite REMnO3 Films (RE = Y, Er, Dy)

“…For Nd 1− x MnO 3−δ ceramics, a single phase is obtained up to x = 0.3−0.4 . Thin films of the solid solutions La 0.8 MnO 3−δ and Nd 0.7 MnO 3−δ were grown by CVD and similar solubility limits were observed than in the bulk. ,, …”

“…This behavior indicates the presence of at least two out-of-plane lattice parameters and can be attributed to the presence of two layers in the film: a strained (or partially strained) layer at the interface with the substrate (with an out-of-plane parameter noted c 1 ) and a relaxed (or partially relaxed) layer on top of it (with an out-of-plane parameter noted c 2 ). Such a two-layer model was proposed for perovskite-type manganite films such as La 0.8 MnO 3 35 or La 0.67 Ca 0.33 MnO 3 grown on (001) LaAlO 3 , 36 La 0.7 Sr 0.3 MnO 3 grown on (001) SrTiO 3 37 or the charge-ordered compound Nd 0.5 Sr 0.5 MnO 3 grown on (001) LaAlO 3 . 38 It was also reported for other oxides such as SrRuO 3 on SrTiO 3 (001).…”

“…49 Thin films of the solid solutions La 0.8 MnO 3-δ and Nd 0.7 MnO 3-δ were grown by CVD and similar solubility limits were observed than in the bulk. 35,48,49 In the case of the hexagonal REMnO 3 structure, a cationic offstoichiometry can also be envisaged with vacancies on the RE and/or Mn sites. Vacancies were proposed for the origin of the large variations of YMnO 3 single crystals prepared either under Bi 2 O 3 flux or by the floating zone technique.…”

Observation of strain and temperature induced changes in the band structure of thin La0.8MnO3−δ films

“…In our previous studies of La 0.8 MnO 3−␦ films, we found an increase in the degree of local distortion of the MnO 6 octahedra with reduced film thickness by near edge x-ray absorption spectroscopy at the manganese K edge. 10,11 Bulk magnetization measurements conducted by superconducting quantum interference device ͑SQUID͒ magnetometry on 6, 30, and 160 nm thick films showed a reduction of the magnetic ordering temperature ͑T c ͒ and magnetic saturation moment with a reduction in thickness. Films of the entire thickness range exhibit metal-like conductivity at low temperature.…”