Strong modification of intrinsic spin Hall effect in FeMn with antiferromagnetic order formation

FeMn films with and without a Cu seed layer were deposited on Y3Fe5O12 (YIG) substrates, and their inverse spin Hall effect (ISHE) was examined through both spin Seebeck effect and spin pumping. From the ISHE voltage, the spin Hall angle of FeMn in YIG/Cu/FeMn is greatly enhanced with its polarity opposite to that in YIG/FeMn. Anisotropic magnetoresistance measurements on the samples with an additional NiFe layer show that the FeMn layers in YIG/Cu/FeMn and YIG/FeMn are antiferromagnetic and paramagnetic, respectively. The present work demonstrates that the antiferromagnetic order in FeMn alloy intensely influence its intrinsic spin Hall effect.