Thermodynamic and transport properties of Ru2−x Fe x CrSi (1.3 ≤ x ≤ 1.8)

Abstract

We have measured the temperature (T) dependences of the electric resistivity, ρ(T), and the specific heat, Cp(T), of the ferromagnetic full-Heusler compound Ru2−xFexCrSi (1.3 ≤ x ≤ 1.8). ρ(T) shows a metallic behavior (∂ρ/∂T > 0) for 20 ≲ T ≤ 300 K and nominal upturn at around 20 K for all samples. In the low-temperature range, Cp(T) can be described by Debye’s T3 law. Although the coefficient of the lattice part of Cp(T), β, is insensitive for the Fe concentration x, the electronic specific heat part, γ, decreases with increasing x. The values of the total densities of states (Dtotal(EF)) estimated from γ were 12.8, 10.1, and 9.6 states/f.u. eV for x = 1.3, 1.6, and 1.8, respectively. The values of majority spin band (D↑(EF)) and the minority spin band (D↓(EF)) were also estimated using γ and the spin polarization P defined by Andreev-reflection experiments.