Occurrence of large perpendicular magnetic anisotropy in bilayered films with nanometer-thick TbFeCo and Al layers

Abstract

For Tb-Fe-Co(MO)/Al bilayered films, dependence of perpendicular magnetic anisotropy constant Ku⊥ on MO layer thickness tMO of 3–300 nm and Al layer thickness tAl of 5 and 100 nm has been investigated. For either tAl, easy magnetization direction was normal to film plane at tMO above 4 nm. Ku⊥ of films with tAl of 5 nm increased drastically with increasing tMO for tMO<10 nm and then assumed a constant value of 4×106 erg/cm3 which is two times larger than that with tAl of 100 nm. This difference in Ku⊥ between them may be attributed to stress induced anisotropy. Estimation of rotational hysteresis loss Wr and its integral R suggests that the mechanism of magnetization reversal may be attributed to incoherent curling mode.