Unconventional magnetoresistance induced by sperimagnetism in GdFeCo

Abstract

We investigate the magnetoresistance of ferrimagnetic GdFeCo across the magnetization compensation temperature T-M. The magnetic field dependence of longitudinal resistivity (rho(xx)) shows opposite trends below and above T-M, and the variation of rho(xx) with B becomes more significant as the temperature decreases. The observed unconventional magnetoresistance is attributed to the sperimagnetism of GdFeCo. Further investigations on the transverse resistivity (rho(xy)) of GdFeCo unveils that, contrary to the recent reports that the transition metal dominates transport of rare-earth transition-metal ferrimagnets, the Gd contribution to magnetoresistance is comparable to the FeCo contribution, showing that the transport of GdFeCo is antiferromagnetic. Our results therefore show that ferrimagnets are a convenient platform for studying antiferromagnetic spin transport and also are potential materials that can enable antiferromagnetic spin devices.