Effect of V doping on magnetic and electrical transport properties of La0.8Sr0.2Co1−xVxO3

The effect of V-doping on the magnetic and electrical transport properties for La0.8Sr0.2Co1−xVxO3 (x=0.00, 0.02, 0.04, and 0.06) has been investigated through X-ray diffraction, magnetization and resistivity measurements. The ferromagnetic order is dramatically suppressed by the V substitution. The magnetic results suggest that the Co3+ and Co4+ ions are both in the intermediate-spin state, indicating that a strong-coupling double exchange between Co3+ and Co4+ intermediate-spin state via t2g-orbitals is the driving force for the ferromagnetic order in the present compound. The resistivity increases as the V doping level increases, in agreement with the magnetic results. Moreover, the transport mechanism at the low temperature is dominated by the variable-range-hopping conduction.