Extraordinary Hall effect of sputtered amorphous ferrimagnetic GdFeCo alloy films

We investigate extraordinary Hall effect of sputtered amorphous ferrimagnetic GdFeCo alloy films using a composite target method. The composite target consists of a FeCo alloy disk and several Gd chips. The alloy film changing from FeCo-rich to Gd-rich phase is realized by manipulating sputtering power during the growth, confirmed by the shift of the compensation point. The sign of the extraordinary Hall resistance is observed to change from positive for FeCo-rich films to negative for Gd-rich films. The reversed sign at magnetic compensation can be ascribed to the combined effect of FeCo and Gd sublattices with opposite sign. A large extraordinary Hall coefficient of 1-2 x 10-8 & omega; cm/emu is derived, which is one order in magnitude larger than that in ferromagnetic [Co,CoFe/Pt] multilayers. This sufficiently large extraordinary Hall coefficient indicates amorphous ferrimagnetic GdFeCo alloy films are promising for the applications in perpendicular magnetoelectronic devices.

Automated summary

We investigate the extraordinary Hall effect of sputtered amorphous ferrimagnetic GdFeCo alloy films using a composite target method. The sign of the extraordinary Hall resistance changes from positive to negative as the alloy film transitions from FeCo-rich to Gd-rich phase. The large extraordinary Hall coefficient indicates the potential applications of amorphous ferrimagnetic GdFeCo alloy films in perpendicular magnetoelectronic devices.