CaRuO₃ is not a paramagnetic material

Magnetic studies of ceramic and single crystal CaRuO₃ samples demonstrate that irreversibility appears in the zero-field-cooled field-cooled curves only when measured at low applied magnetic fields. A small hysteresis loop opens at low temperatures, and the remanent magnetization decreases with temperature and disappears at ∼90 and 71 K for the ceramic and crystal samples, respectively. The easy axis for the magnetization is in the [001]. Mössbauer studies of 1% ⁵⁷Fe doped in CaRuO₃ show a magnetic sextet at 4.1 K which disappears at 90 K. It is proposed that CaRuO₃ is not paramagnetic, but rather shows the characteristics of short range magnetic interactions, possibly as spin-glass-like behavior. ⁵⁷Fe ions experience an exchange field from their magnetic Ru neighbors and also become magnetically ordered.