Correlation among magneto-, electrical- and thermal-transport properties in SrRuO${}_3$ films

The magneto-, electrical- and thermal-transport properties of SrRuO${}_3$ (SRO) films have been investigated. The magnetization (M), relative resistivity (Δρ) and relative Seebeck (ΔS) near T${}_C$ follow a scaling law, M ~ (T${}_C$-T)${}^{\alpha }$, Δρ${}_{SP}$ ~ (T-T)${}^{2\beta }$ and ΔS ~ (T${}_C$-T)${}^{2\gamma }$, respectively. The values α = 0.394, β = 0.401 and γ = 0.421 for the (001)-SRO thin films are well fitted with mean-field critical exponents. While critical exponent α = 0.365, β = 0.357 and γ = 0.363 for the (111)-SRO thin films belong to Heisenberg ferromagnetic behavior. A T${}^2$ temperature dependence of resistivity below 30 K corresponds to a Fermi-liquid state. In the Fermi-liquid regime, the MR(%) =|ρ(H)−ρ(0)|/ρ(0) × 100% and MS(%) =|S(H)−S(0)|/S(0) × 100% are quadratic at low field and almost linear for large field without saturation until 70 kOe. Furthermore, dM/dT, dρ/dT and dS/dT show a linear relationship, indicating the intrinsic electrical-, thermal- and magneto-transport properties are coupled.