Analyzing the magnetic profile in NiFe/NiO bilayers

- The magnetic profile of the Si(100)/NiO(35nm)/NiFe(10nm)/Ta(1nm) has been obtained by X-ray absorption spectroscopy.
- Evidence that the magnetic moments, for thick NiFe layers, are comparable with the bulk values.
- There is no charge between Ni and Fe in the inner part of the NiFe layer.
- A reduction of the morb/mspineff has been found at the NiFe/NiO interface.

The magnetic profile of the Si(100)/NiO(35 nm)/NiFe(10 nm)/Ta(1 nm) sample has been obtained by X-ray absorption spectroscopy (XAS) and the X-ray magnetic circular dichroism (XMCD). Two experimental procedures were used. In the procedure 1, the magnetic depth profile has been determines using samples deposited with different NiFe thicknesses, Si(100)/NiO(35 nm)/NiFe(t)/Ta(1 nm), t=1,3,5,7,10nm. In procedure 2, the sample (NiFe=10 nm), was thinned by several in situ sputtering cycles with Ar+ ions, followed by XAS and XMCD analysis. In both procedures, the calculated magnetic moments values tend to decrease close to interface with the NiO antiferromagnetic (AF) layer, however, this decreasement is more evidenced in the sputtered sample. There is no charge transfer between Ni and Fe in the inner part of the NiFe layer, a reduction of the morb/mspineff has been found at the NiFe/NiO interface. Procedure 1 emerged as the most indicated to analyse the interface region.