Epitaxial thin films of ordered double perovskite SrLaVMoO 6
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Epitaxial thin films of ordered double perovskite SrLaVMoO6 Katsutoshi. Sanbou1, Keita. Sakuma1, Tetsuya. Miyawaki1, Kenji. Ueda1 and Hidefumi. Asano1 1
Dept. of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
ABSTRACT Epitaxial thin films of SrLaVMoO6 with an ordered double perovskite structure have been grown on (001) and (111) SrTiO3 substrates by magnetron sputtering. The optimized (111) film exhibited a clear (111) diffraction peak, which is a superlattice reflection of double perovskite unite cell, indicating clear B-site ordering. Temperature dependences of resistivity ȡ show metallic behavior and transition point at 140~150 K, of which behavior is reminiscent of the electrical properties of materials showing long-range magnetic or antiferromagnetic order. XPS results of the Mo 3d core level spectra are discussed in terms of the B-site ordering and oxygen nonstoichiometry. INTRODUCTION Half-metallic (HM) compounds [1,2], which are compounds with only one spin channel present at the Fermi energy (EF), have received significant recent attention due to their potential applications in spintronics and related fields. Ideally, they show 100% spin polarization due to a band gap for the other spin channel at EF. In stoichiometric half-metallic compounds, the energy gap between spin channels results in the quantization of the spin moment, which is a central feature of the half-metallic character. As a special case of half-metallic materials, van Leuken and de Groot [3] proposed the concept of half-metallic antiferromagnet (HMAF), which shows both fully spin-polarized charge transport and zero net magnetic moment. The prospect of getting a fully spin-polarized current from a metal that has no magnetic field provides not only fertile playground for fundamental research but also conceivable new spintronic devices that rely on the spin polarization of the carriers. Furthermore, the likelihood of a novel form of superconductivity, that is, spin-triplet superconductivity, in HMAF’s has been proposed [4], which intensifies interest in these unique systems. There have been several theoretical studies [5-11] based on the band structure calculations that predict candidates for HMAF states within the class of double perovskite compounds. The mixed-cation double perovskites AA’BB’O6 provide a fertile environment for tailoring the desired properties, owing to the existence of potentially very large number of members, and strong coupling between magnetic ordering and electronic properties. Among the candidate HMAF materials, SrLaVMoO6 is of special interest from both theoretical and experimental view points. Ueharaet al. [12] reported the synthesis, and the magnetic and electrical properties of bulk polycrystalline SrLaVMoO6, and suggested that the compound was an antiferromagnetic metal with a Neel temperature TN of 130 K. Gotohet al. [13,14] reported observation of coexistence of antiferromagnetic nature and high spin polarization in bulk polycrystalline SrLaVMoO6with B
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