Depth sensitive exchange coupled spin structure in NiFeFeMn bilayer

Magnetization mechanisms in NiFe and NiFeFeMn layered systems have been studied using vibration sample magnetometry (VSM) and transverse Kerr effect spectrometry (TKE). The TKE signal was examined at the wavelengths of 300, 500, and 700 nm and at various fields from 12 to 85 Oe at each wavelength by aiming at a depth sensitive exchange coupled magnetic profile in the probed ferromagnetic layer. An attempt has been made to correlate the features from the M-H curve profiles measured using VSM under dc magnetic field and TKE with ac magnetic field to the exchange coupled spin structures. The results point toward a short range order of biquadratic exchange coupling near the interface. Based on the data and analysis, possible spin structures were proposed and depth profiles of decomposed magnetization due to biquadratic and bilinear exchange couplings were reported.