Exchange interactions in NiFe/Ta/IrMn heterostructures under conditions of tantalum deficiency

In the NiFe/Ta/IrMn structures, the contributions of two types of exchange interactions are separated at the NiFe/IrMn interface, partially separated by non-magnetic Ta fragments. The first “contact” exchange corresponds to the NiFe/IrMn fragments. The second “interlayer” exchange is provided by the Ta conduction electrons in the NiFe/Ta/IrMn fragments. A comparison of the temperature dependences of the exchange bias in heterostructures with varied Ta spacer at fixed parameters of the ferromagnetic layers allowed us to separate the contributions of the above types of exchange interactions and to establish their temperature dependences. The energies of the exchange interactions in the NiFe/IrMn and NiFe/Ta/IrMn fragments were determined.