Evidence of a correlation between magnetic and structural transitions in Y 2−x Zn x Ru 2 O 7 pyrochlore compounds

We report on an experimental investigation of the magnetic and structural properties of the Y 2−x Zn x Ru 2 O 7 pyrochlore system as a function of the Zn doping in the range 0.00 ≤ x ≤ 0.20. Magnetization and muon spin relaxation measurements show that the antiferromagnetic transition typical of the undoped compound at T N = 77 K is slightly reduced and broadened in the Zn doped sample. Extended X-ray absorption fine structure measurements show a peak in the Ru–O(1) first shell Debye–Waller factor at a temperature T DW ≈ T N , giving evidence for a strong magnetoelastic coupling detected up to x = 0.10. A local precursor order–disorder transition at T * > T N is also observed up to x = 0.10. For x > 0.10 these local structural features are hidden due to the increasing local lattice distortion induced by the Zn 2+ dopant whereas the magnetic transition is still present.