Spin-Peierls state versus Néel state in doped CuGeO3.

No abstract

Half-metallic antiferromagnets are the ideal materials for spintronic applications since their zero magnetization leads to lower stray fields and thus tiny energy losses. Starting from the Mn2VAl and Mn2VSi alloys we substitute Co and Fe for Mn and we show by means of first-principle electronic structure calculations that the resulting compounds are ferrimagnets. When the total number of valence electrons reaches the magic number of 24 the Fe-doped compounds are semi-metals and thus non-magnetic while the Co-doped ones show the desirable half-metallic antiferromagnetic character. The compounds are very likely to be synthesized experimentally since the parent compounds, Mn2VAl and Co2VAl, have been already grown in the Heusler L21 lattice structure.

Abstract.Using a state-of-the-art full-potential electronic structure method within the local spin density approximation, we study the electronic and magnetic structure of Mn 2 V-based full Heusler alloys: Mn 2 VZ (Z=Al, Ga, In, Si, Ge, and Sn). We show that small expansion of the calculated theoretical equilibrium lattice constants restores the half-metallic ferrimagnetism in these compounds. Moreover a small degree of disorder between the V and Z atoms, although iduces some states within the gap, it preserves the Slater-Pauling behaviour of the spin magnetic moments and the alloys keep a high degree of spin-polarisation at the Fermi level opening the way for a half-metallic compensated ferrimagnet.

No abstract