Ru99 perturbed angular correlation and Mössbauer effect investigations of SrRuO3 and CaRuO3

Ru99 Mössbauer spectroscopy (ME) and Ru99γ– γ perturbed angular correlation measurements were applied to investigate magnetic properties of SrRuO3 and CaRuO3 in the wide temperature range. In case of ferromagnetic SrRuO3, the hyperfine magnetic field at Ru site Hhf0=327(2) kOe was determined and compared with the previous results obtained by ME and NMR methods. Possible contributions to the HhfHhf in SrRuO3 and its temperature dependence are discussed. For CaRuO3, strong evidence of lack of any freezing of Ru magnetic moments down to 1.8 K is given, which excludes any spin-glass or short-range order. A possible origin of the observed magnetization irreversibility is qualitatively discussed.