  We investigate the electronic structure and magnetic properties of four
quaternary Heusler alloys ZrMnVZ and ZrCoFeZ (Z=Si, Ge) by using
first-principle calculations. It is shown that ZrMnVSi, ZrMnVGe and ZrCoFeSi
are half-metallic ferromagnets with considerable half-metallic gaps of 0.14,
0.18 and 0.22 eV, respectively. ZrCoFeGe is a nearly half-metallic, the changes
of properties for this alloy under pressure is investigated, the spin
polarization of this alloy is 98.99\% at equilibrium lattice constant.
