Low-temperature specific heat for ferromagnetic and antiferromagnetic orders in CaRu1−xMnxO3

Low-temperature specific heat of CaRu1−xMnxO3 was measured to clarify the role of d electrons in ferromagnetic and antiferromagnetic orders observed above x = 0.2. Specific heat divided by temperature Cp/T is found to roughly follow a T2 function, and relatively large magnitudes of electronic specific heat coefficient γ were obtained in wide x range. In particular, γ is unchanged from the value at x = 0 (84 mJ/K2 mol) in the paramagnetic state for x ≤ 0.1, but linearly reduced with increasing x above x = 0.2. These features of γ strongly suggest that itinerant d electrons are tightly coupled with the evolution of magnetic orders in small and intermediate Mn concentrations.