Magnetic Properties of SrRuO3 and CaRuO3

Magnetization measurements of SrRuO3 and CaRuO3 confirm that SrRuO3 is ferromagnetic with TC = (160±5) °K and that CaRuO3 has antiferromagnetic exchange interactions dominant. They further identify in CaRuO3 a Néel temperature TN = (110±10) °K and parasitic ferromagnetism below TN having a σ0 = (3.2±0.4) × 10−2 emu/g at 4.2°K. High-field (to 125 kOe) magnetization and neutron-diffraction data for SrRuO3 are consistent with a reduced spontaneous ferromagnetic moment μ0 = (1.4±0.4) μB and no ordered antiferromagnetic component. Resistivity measurements confirm a low resistivity (ρ<10−3Ω·cm) at room temperature having a metallic temperature coefficient. It is concluded that both compounds represent spontaneous collective-electron magnetism and that the reduced moment of SrRuO3 is due to holes in both the up-spin and down-spin bands. Antiferromagnetic CaRuO3 is predicted to have narrower ``4d'' bands.