Electron Transport Properties of Eu(Cu_1 − xAg_x)₂Si₂ (0 ≤ x ≤ 1): Initiation of Transition Eu²⁺ ↔ Eu^2.41+ in the Intermediate Valence State

Table 1

Parameters of temperature dependences of thermopower and resistivity in the system Eu(Cu_1 − xAg_x)₂Si₂ (0 ≤ x ≤ 1).

Composition	T^αmax; (K)	αmax; (μV/K)	T−/+; (K)	ρ300; (μΩ·cm)	ρ6 K/ρ300 K	ϑeff
1-EuCu2Si2	142	30.3	300	260	0.24	2.41
2-Eu(Cu0.95Ag0.05)2Si2	142	33.0	300	270	0.24	2.38
3-Eu(Cu0.875Ag0.125)2Si2	28.0	21.5	183	139.12	0.70	2.34
4-Eu(Cu0.75Ag0.25)2Si2	20.7	15.4	146	71.83	0.62	2.21
5-Eu(Cu0.50Ag0..50)2Si2	13.5	4.28	46	56.28	0.54	2.08
6-Eu(Cu0.25Ag0.75)2Si2	13.5	2.6	32	42.08	0.57	2.00
7-Eu(Cu0.125Ag0.875)2Si2	13.5	1.4	25	32.80	0.49	2.00
8-EuAg2Si2	—	—	—	33.30	0.34	2.00

T^α_max, the temperature of the maximum thermopower α_max; α_max, the value of α_max; T_−/+, the temperature of the thermopower transition from negative to positive values; ρ₃₀₀, the value of ρ at 300 K; ρ6 K/ρ300 K, the ratio of the value of the resistivity at 6 K and 300 K; and ϑ_eff, the effective valence of europium according to X-ray L_III-absorption spectroscopy data.