Itinerant electron magnetism in CaRu1−xMnxO3 (0 ≤ x ≤ 0.5)

The effect of Mn substitution in paramagnetic metal CaRuO3 was studied by magnetization and neutron diffraction measurements. Development of ferromagnetic order is observed for x > =0.2 in CaRu1-xMnxO3. For the sample with x = 0.4, the Curie temperature of ~160 K is obtained from the Arrott plot and the ratio of effective moment and saturation moment Peff/M(0) is estimated to be ~4.8. We further found that the magnetization is significantly suppressed with decreasing temperature T below ~90 K. In the neutron diffraction experiment at T = 15 K, we observed the evolution of a magnetic Bragg peak originating from the G-type antiferromagnetic order as well as the ferromagnetic one. This strongly suggests that both ferromagnetic and antiferromagnetic states are coexistent with each other at low temperatures. In the M(T)02 against T2 plot (here, M(T)0 is a spontaneous magnetization estimated from the Arrott plot), M(T)02 linearly increases with decreasing T2 in the ferromagnetic region between ~90 and 160 K. The ferromagnetic properties of the CaRu1-xMnxO3 system (x < =0.5) are well explained in terms of spin fluctuation theory based on the itinerant electron model rather than the localized spin model.