SrRuO 3 thin films grown on MgO substrates at different oxygen partial pressures
- PDF / 794,740 Bytes
- 6 Pages / 584.957 x 782.986 pts Page_size
- 58 Downloads / 190 Views
A comprehensive study of SrRuO3 thin films growth on (001) MgO substrates by pulsed laser deposition in a wide oxygen pressure range from 10 to 300 mTorr was carried out. The experimental results showed a correlation between the lattice constants, resistivity, and oxygen partial pressures used. Ru deficiency detected only in films deposited at lower oxygen pressures (,50 mTorr), resulted in an elongation of the in-plane and out-of-plane lattice constants and an increase in the film resistivity. When deposited with oxygen partial pressure of 50 mTorr, SrRuO3 films had lattice parameters matching those of bulk SrRuO3 material and exhibited room temperature resistivity of 320 lXcm. The resistivity of SrRuO3/MgO films decreased with increasing oxygen partial pressure.
I. INTRODUCTION
SrRuO3 is a ferromagnetic metal oxide with outstanding thermal conductivity, stability, and high resistance to chemical erosion.1–3 Thin films of SrRuO3 have been widely used as a buffer layer for developing superconducting YBa2Cu3O7 d films3 and as a conducting electrode for ferroelectric capacitors.4–6 At room temperature, SrRuO3 exhibits orthorhombic perovskite structure with lattice constants a 5 5.56 Å, b 5 5.55 Å, and c 5 7.86 Å,3,7 which can also be described as a pseudocubic perovskite structure with lattice constants of a 5 3.93 Å.3,8 With increasing temperature, the orthorhombic structure transforms into a tetragonal structure at 547 °C and subsequently transforms into a cubic structure at higher temperature (at 677 °C).9,10 Polycrystalline SrRuO3 has a resistivity of around 1130 lXcm, whereas the resistivity of single crystalline SrRuO3 is around 280 lXcm at room temperature.11 The microstructural and electrical properties of SrRuO3 thin films strongly depend on the deposition conditions. Substrate temperature and oxygen pressure are of prime importance when pulsed laser deposition (PLD) is used. Epitaxial SrRuO3 thin films have been successfully grown by PLD on various single crystal substrates, such as SrTiO3,11–19 LaAlO3,7,20–22 and MgO.1,23 When SrRuO3 is deposited on (001) SrTiO3 substrate, film can grow epitaxially with [001], [110] or [110] planes parallel to the SrTiO3 surface, which leads to six possible SrRuO3 domain structures and orientations.13,16 The domain structures of SrRuO3 films grown on LaAlO3 substrates a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2012.409 702
J. Mater. Res., Vol. 28, No. 5, Mar 14, 2013
http://journals.cambridge.org
Downloaded: 04 Feb 2015
are different from those grown on SrTiO3. SrRuO3 thin films on (001) LaAlO3 substrate consist of all three types of the orientation domains, which are randomly distributed in the film.23 In contrast to the atomically flat surface of SrRuO3 films on SrTiO3 substrate, the SrRuO3 film grown on LaAlO3 substrate has a rough surface with a sinusoidal-like modulation. The reason for these differences was ascribed as an effect of lattice mismatch across the film–substrate interface.22 Zakharov et al.11 have shown that SrRuO3/
Data Loading...
