Effect of pressure on thermopower of EuNi₂Ge₂

Pressure Effect on Transport Properties of EuNiGe3

“…Although T a shows no pressure dependence, an anomaly at T a in S (T ) is pronounced by applying pressure. The ρ and S of EuNiGe 3 indicate the small values in comparison with those of EuNi 2 Ge 2 [5]. The spectral electrical conductivity σ in Eq.…”

“…The valence state of some Eu compounds is changed by temperature, magnetic field and pressure. For example, the compound of EuNi 2 Ge 2 in the 122 system is an antiferromagnetic below T N ≈ 30 K with an effective moment µ eff ≈7.7 µ B /Eu, indicating the 4f 7 (Eu 2+ ) electron configuration in the ground state [2], and shows the first-order valence transition from Eu 2+ to Eu 3+ at T v ≈ 100 K under pressure of P ≈ 2 GPa [3][4][5]. On the other hand, few studies on EuNiGe 3 compound with the BaNiSn 3 -type crystal structure, where the half of the atomic sites of Ni in EuNi 2 Ge 2 are replaced by Ge, have been performed [6].…”

Anisotropic Magnetic Phase Diagrams in EuRh2Si2

“…In EuRh 2 Si 2 , the magnetic susceptibility data at µ 0 H = 1 T exhibit anisotropic features below about 100 K (≫ T N = 23.8 K), and the anisotropy ratio becomes χ [100] /χ [001] ≃ 2.5 at 1.8 K. In addition, the magnetization curves also show a large anisotropy, which is reflected in the difference of saturation magnetic fields: H [100] c ≃ 2.5 T and H [001] c ≃ 10 T. Note that the anisotropic magnetism was also reported for other Eu-based ThCr 2 Si 2 compounds such as EuCo 2 Ge 2 [8,9], EuRh 2 Ge 2 [10], EuIr 2 Si 2 [11], and EuNi 2 Ge 2 [10]. Among these compounds, the pressure-induced valence transition was observed in EuRh 2 Si 2 [2,3], EuNi 2 Ge 2 [12,13], and EuCo 2 Ge 2 [14] at P v ≃ 1, 2, and 3 GPa, respectively. It is interesting whether there is a relationship between the proximity to the valence transition and the large magnetic anisotropy or not, and this is left as a future study.…”

Magnetism and Transport Properties of EuNiSi3

“…For example, many Europium-base intermetallic compounds of RT 2 X 2 , (R= rare earth, T=transition metal, and X=Si, Ge) with ThCr 2 Si 2 -type tetragonal structure exhibit a change in valence as function of temperature, atomic substitution, pressure and magnetic field from a divalent to a trivalent state. In this series, EuNi 2 Ge 2 , in which the Eu atoms are in the Eu 2+ (J = 7/2) state, manifests an antiferromagnetic order at the T N ≈ 30 K. On the other hand, EuNi 2 Si 2 , in which Eu atoms are in the Eu 3+ (J = 0) state, manifests a Pauli's temperature-independent magnetic susceptibility [2,4,5].…”