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arXiv · 1011.2559

Structure, Transport and Magnetic properties in La$_{2x}$Sr$_{2-2x}$Co$_{2x}$Ru$_{2-2x}$O$_{6}$

P. S. R. Murthy·K. R. Priolkar·P. A. Bhobe·A. Das·P. R. Sarode·A. K. Nigam
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Abstract

The perovskite solid solutions of the type La$_{2x}$Sr$_{2-2x}$Co$_{2x}$Ru$_{2-2x}$O$_{6}$ with 0.25 $\leq$ x $ \leq $ 0.75 have been investigated for their structural, magnetic and transport properties. All the compounds crystallize in double perovskite structure. The magnetization measurements indicate a complex magnetic ground state with strong competition between ferromagnetic and antiferromagnetic interactions. Resistivity of the compounds is in confirmation with hopping conduction behaviour though differences are noted especially for $x$ = 0.4 and 0.6. Most importantly, low field (50Oe) magnetization measurements display negative magnetization during the zero field cooled cycle. X-ray photoelectron spectroscopy measurements indicate presence of Co$^{2+}$/Co$^{3+}$ and Ru$^{4+}$/Ru$^{5+}$ redox couples in all compositions except $x$ = 0.5. Presence of magnetic ions like Ru$^{4+}$ and Co$^{3+}$ gives rise to additional ferromagnetic (Ru-rich) and antiferromagnetic sublattices and also explains the observed negative magnetization.

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P. S. R. Murthy, K. R. Priolkar, P. A. Bhobe, A. Das, P. R. Sarode, A. K. Nigam. 2010-11-11. Structure, Transport and Magnetic properties in La$_{2x}$Sr$_{2-2x}$Co$_{2x}$Ru$_{2-2x}$O$_{6}$. https://doi.org/10.1016/j.jmmm.2010.11.024

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