Spin to Charge Conversion in Semiconducting Antiferromagnetic Co3O4

Power efficient and faster spintronic devices require high spin current propagation efficiency from a ferromagnet (FM) to high spin orbit coupling material. Antiferromagnets (AFM) exhibiting high spin orbit coupling and faster spin dynamics have drawn great attention in such studies. Efficient spin current propagation in metallic AFMs via conduction electron showed promising results in spin to charge conversion physics. Recently, the insulating AFMs are also found to exhibit efficient spin current propagation due to the presence of magnonic modes. The semiconducting AFM Co3O4 is expected to show promising results in spin to charge conversion studies due to the simultaneous presence of magnon modes and conduction electrons. In this context, spin pumping and inverse spin Hall effect studies are carried out on a series of Co3O4(t nm)/Co(22 nm) samples where the t value varies from 0 to 26 nm. Damping analysis reveals that the spin diffusion length of Co3O4 is 2.5 ± 0.5 nm which is large in comparison to metallic AFMs. The maximum Hall angle of Co3O4 is found to be 0.26. A high spin transparency of 65.8% indicates efficient spin current propagation in the samples.