De Haas-van Alphen effect and fermi surface properties in nearly ferromagnet SrCo₂P₂

We grew high-quality single crystals of SrCo₂P₂ with the ThCr₂Si₂-type tetragonal structure, and clarified the Fermi surface properties by carrying out de Haas-van Alphen (dHvA) experiments and energy band calculations. SrCo₂P₂ is known to be a nearly ferromagnetic compound, where the magnetic susceptibility follows the Curie-Weiss law above 200 K, with the effective magnetic moment μ_eff = 1.72 μ_B/Co, but becomes almost constant below about 100 K. The electronic specific heat coefficient γ is thus relatively large, being γ = 40 mJ/(K²·mol). Detected dHvA branches possess the corresponding cyclotron effective masses m_c∗, ranging from 0.87 to 7.2 m₀ (m₀: rest mass of an electron). The angular dependences of the dHvA frequencies are well explained by the results of full-potential linearized augmented plane wave (FLAPW) energy band calculations, revealing a multiply-connected band 25^th hole Fermi surface and a compensated nearly cylindrical band 26^th electron Fermi surface. It is thus concluded that the electronic state of SrCo₂P₂ is nearly three-dimensional rather than two-dimensional.