Direct evidence for minority spin gap in the Co2MnSi Heusler compound

作者：Andrieu Stephane^*; Neggache Amina; Hauet Thomas; Devolder Thibaut; Hallal Ali; Chshiev Mairbek; Bataille Alexandre M; Le Fevre Patrick; Bertran Francois

来源：PHYSICAL REVIEW B, 2016, 93(9): 094417.

DOI：10.1103/PhysRevB.93.094417

Half metal magnets are of great interest in the field of spintronics because of their potential full spin polarization at the Fermi level (E-F) and low magnetization damping. The high Curie temperature and the predicted 0.7 eV minority spin gap make the Co2MnSi Heusler compound very promising for applications. We investigated the half-metallic magnetic character of this compound using spin-resolved photoemission, ab initio calculation, and ferromagnetic resonance. At the surface of Co2MnSi, a gap in the minority spin channel is observed, leading to 100% spin polarization. However, this gap is 0.3 eV below E-F, and a minority spin state is observed at EF. We show that a minority spin gap at EF can nevertheless be recovered either by changing the chemical composition of the compound or by covering the surface by Mn, MnSi, or MgO. This spin-gap recovery results in extremely small damping coefficients, reaching values as low as 7 x 10(-4).

• 出版日期2016-3-15
• 单位中国地震局