De Haas-Van Alphen Effect And Fermi Surface Properties In Ferromagnet Laco2p2 And Related Compounds

We grew single crystals of a ferromagnet LaCo2P2 and an antiferromagnet CaCo2P2, and clarified the magnetic properties by measuring the electrical resistivity, specific heat, magnetic susceptibility, and magnetization. For LaCo2P2, we also carried out the de Haas-van Alphen (dHvA) experiment. Detected dHvA branches are well explained by the results of energy band calculations using a full-potential linearized augmented plane wave method within the local spin density approximation, where the ferromagnetic state is assumed. The cyclotron effective masses are (2-3)m(0) (m(0): rest mass of an electron). The present relatively large cyclotron masses in LaCo2P2 are due to ferromagnetic correlations of Co-3d conduction electrons, which are compared with much larger cyclotron masses of (3-7)m(0) for a nearly ferromagnet SrCo2P2.