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Single-Step Synthesis of Sr4V2O6Fe2As2: The Blocking Layer Based Potential Future Superconductor

Research paper by Anand Pal, Arpita Vajpayee, R. S. Meena, H. Kishan, V. P. S. Awana

Indexed on: 06 Jun '09Published on: 06 Jun '09Published in: Journal of Superconductivity and Novel Magnetism



Abstract

We report synthesis, structural details and transport measurements on Sr4V2O6Fe2As2. Namely, the stoichiometric amounts of V2O5+1/2×SrO2+7/2×Sr+2×FeAs are weighed mixed, ground thoroughly and palletized in rectangular form in a glove box in high purity Ar atmosphere. The pellet is further sealed in an evacuated (10−5 torr) quartz tube and put for heat treatments at 750 and 1150°C in a single step for 12 and 36 hours respectively. Finally the quartz ampoule is allowed to cool naturally to room temperature. The as-synthesized sample is black in color. The compound crystallized in P4/nmm space group with lattice parameters a=b=3.925 Å and c=15.870 Å. Also seen are some small impurity lines. The compound did not exhibit superconductivity but instead a spin density wave (SDW) like metallic step at around 175 K is seen in R(T) measurements. Principally in [FeAs]−1{Sr4V2O6}C[FeAs]−1 the net value of blocking layer charge C must be either less or more than 2, to let it be electron or hole type superconductor respectively. Efforts are under way to achieve superconductivity in the studied system.