We investigated room-temperature exchange bias phenomenon and training effect in SiO2/Ru(40 nm)/Co(t nm)/
IrMn3(5 nm)/Ta(5 nm) with varying Co layer thicknesses t = 2, 3, 5, 8, 10, and 20 nm. Consecutive hysteresis
loop measurements by longitudinal magneto-optical Kerr effect (L-MOKE) revealed the presence of both
athermal and thermal training effects in the Co/IrMn3 ferromagnetic/antiferromagnetic bilayers. The athermal
training effect is more prominent as the Co layer thickness increased. We also observed that the training effect
constant γ increased with increasing Co layer thickness, suggesting that thicker samples were closer to equilibrium,
as interpreted by Binek’s relaxation model. This study not only advances our understanding of the
exchange bias phenomenon and training effect in the Co/IrMn3 system but also may offer their potential for use
in neuromorphic devices.