CaRuO3 thin films were synthesized on SrTiO3 substrates by pulsed laser deposition. Detailed microstructure analysis by transmission electron microscopy revealed the pseudoheterostructure in CaRuOfilms. It consists of a coherently strained cubic CaRuOlayer contacted with substrate, as well as a strained orthorhombic CaRuO3layer. The orthorhombic CaRuO3layer is composed of two types of domains. The ferromagnetic property of the pseudoheterostructure CaRuO3was revealed by superconducting quantum interference device measurement. This is due to the cubic CaRuO3layer, which is supported by first-principle calculations. The formation mechanism of pseudoheterostructure in ultrathin CaRuO3thin films was proposed.

This paper is published on APL.

Link to the full text: http://apl.aip.org/resource/1/applab/v96/i18/p182502_s1

4 May, 2010

  

 

 

Topological insulators represent a new state of quantum matter recently discovered with insulating bulk but conducting surface states formed by an odd number of Dirac fermions. In this Letter, we report our recent progress on the study of electronic structures of ex-situ grown topological insulator thin films by angle resolved photoemission spectroscopy (ARPES). We successfully obtained the topological band structures of molecular beam epitaxial HgTe and vapor–solid grown Bi2Te3 thin films after proper surface cleaning procedures. This new development will not only enable us to study more topological insulators that cannot be measured by conventional in-situ ARPES technique (e.g. by cleaving or growing samples in-situ), but also open the door to directly characterize the electronic properties of topological insulators used in functional devices.

文章作为封面,发表在physica status solidi-Rapid Research Letters 7, 130 (2013)

全文链接:http://onlinelibrary.wiley.com/doi/10.1002/pssr.201206400/abstract

封面链接:http://onlinelibrary.wiley.com/doi/10.1002/pssr.201390000/abstract

pss

Highly crystalline quality c-axis epitaxial nLaFeO3–Bi4Ti3O12 (n = 0.5,1.0,1.5) thin films were deposited on SrTiO3 (001) substrates by pulsed laser deposition. The x-ray diffraction and transmission electron microscopy characterizations confirm that there are designed even-odd number perovskite-block structures in n = 0.5 and 1.5 films while it has even-even number ones in n = 1.0 films. The remarkable physical property of n = 0.5 and 1.5 samples is the presence of ferrimagnetism even up to room temperature. While it is antiferromagentic property in n = 1.0 sample. The observed ferrimagentism is explained qualitatively by considering the crystal structure in nLaFeO3–Bi4Ti3O12.

This paper is published on APL.

Link to the full text: http://apl.aip.org/resource/1/applab/v98/i21/p212501_s1

23 May, 2011

  

 

 

The thickness-dependent metal–insulator transition is observed in meta-stable orthorhombic
SrIrO3 thin films synthesized by pulsed laser deposition. SrIrO3 films with thicknesses less
than 3 nm demonstrate insulating behaviour, whereas those thicker than 4 nm exhibit metallic
conductivity at high temperature, and insulating-like behaviour at low temperature.
Weak/Anderson localization is mainly responsible for the observed thickness-dependent
metal–insulator transition in SrIrO3 films. Temperature-dependent resistance fitting shows that
electrical-conductivity carriers are mainly scattered by the electron–boson interaction rather
than the electron–electron interaction. Analysis of the magneto-conductance proves that the
spin–orbit interaction plays a crucial role in the magneto-conductance property of SrIrO3.

SrIrO3

文章发表在J. Phys.: Condens. Matter 25, 125604 (2013).

全文链接:http://iopscience.iop.org/0953-8984/25/12/125604/

Orthorhombic YMnO3 thin films were epitaxially grown on bare and LaNiO3 buffered (001)–SrTiO3 substrates by pulsed laser deposition under various oxygen pressures from 5 to 30 Pa. The crystal structure and microstructure of these films have been characterized by both X-ray diffractions and transmission electron microscopy. The leakage current, modeled as the space charge limited current (SCLC) mechanism, decreased significantly with the increase of oxygen content. It is further found that the magnetic property of films is greatly enhanced in YMnO3 films grown under high oxygen pressure, which can be explained decreased oxygen vacancies. In addition, bipolar switching behavior was obtained only in the films grown under 30 Pa oxygen pressure, which is attributed to the decrease of voltage-driven oxygen vacancy migration.

This paper is published on Applied Surface Science.

Link to the full text: http://www.sciencedirect.com/science/article/pii/S0169433211006349

July, 2011

  

 

 

Page 1 of 3