Structural and magnetic properties of UHV-evaporated Fe/Tb multilayers: Effect of the substrate temperature
Abstract
Two series of (Fe/Tb)20 multilayers deposited at two temperatures (150 K and 300 K) were investigated at room temperature by x-ray diffraction, conversion electron Mössbauer spectrometry, and magnetic measurements. The Fe layer thickness is varying in a large range (0.9-5.3 nm), while the Tb layer thickness is fixed to 1.9 nm. Because of the two different types of amorphous modulated structures obtained at the two deposition temperatures, the crystallization of the Fe layers occurs following two different processes for the two series. Then, when the Fe layers are crystallized, experimental Mössbauer and magnetic results indicate a similar layered structure with the same extension for the Fe-Tb interfaces at the same Fe thickness. For both series, when the crystallization of the Fe layers occurs, an enhancement of the perpendicular magnetic anisotropy (PMA) produced by a sharpening of the interfaces is evidenced. The strong PMA observed in the thinner (bcc-Fe/Tb) multilayers grown at 300 K comes from the dominant interface anisotropy compared to the volume anisotropy due to the thin bcc-Fe thickness. For (bcc-Fe/Tb) multilayers the variation of the saturation magnetization as a function of the Fe thickness allows us to quantify the different magnetic zones inside the multilayers. The deduced anisotropy constants for the interfaces and the volume are KS=2.32 mJ/m2 and Kv=-1.76×106 J/m3.
- Publication:
-
Physical Review B
- Pub Date:
- September 2001
- DOI:
- 10.1103/PhysRevB.64.094415
- Bibcode:
- 2001PhRvB..64i4415R
- Keywords:
-
- 75.70.Cn;
- 75.30.Gw;
- 76.80.+y;
- Magnetic properties of interfaces;
- Magnetic anisotropy;
- Mossbauer effect;
- other gamma-ray spectroscopy