We report a comprehensive study of the structural, magnetic, and electrical properties of La-substituted Y2Ru2O7 pyrochlore ruthenates. While the synthesis of pure La2Ru2O7 remains elusive, partial substitution of La3+ into Y2Ru2O7 is achievable, providing a tunable platform to systematically modify the lattice. The larger ionic radius of La3+ expands the lattice, potentially altering the Ru 4d bandwidth and magnetic exchange pathways. The compound Y1.75La0.25Ru2O7 thus bridges the gap between well-characterized Y2Ru2O7 and hypothetical La2Ru2O7, enabling a controlled investigation of A-site size effects, local structural distortions, and their impact on frustrated magnetism and correlated electronic behavior. As a nonmagnetic dopant, La3+ isolates lattice effects on the Ru sublattice without introducing additional magnetic contributions. Magnetic measurements reveal a systematic suppression of antiferromagnetic ordering and a reduction of magnetic frustration, along with field-insensitive spin-glass-like behavior, consistent with geometrically frustrated magnetism. Electrical transport measurements indicate semiconducting behavior over the entire temperature range. The temperature-dependent resistivity follows Mott’s three-dimensional variable-range hopping model, and the onset of Ru 4d spin ordering significantly modifies carrier scattering, leading to pronounced resistivity anomalies near the magnetic transition.
Chatterjee et al. (Mon,) studied this question.