A-site substitution of SrRuO3 using La, K and Pb

We have investigated Sr1−xLax/2Kx/2RuO3 and Sr1−xPbxRuO3, which have a larger average size of the A-site cations. They manifest a gradual loss of ferromagnetism in a similar way as their counterparts with smaller A-site cations. There is also evidence for a magnetism-suppressing disorder effect similar to that observed in Sr1−xLax/2Nax/2RuO3. Therefore, the Stoner ferromagnetism in SrRuO3 is rather unique and cannot be easily tuned by lattice distortion to yield a higher Curie temperature.