Induced magnetic anisotropy features in FeCrSiBNbCu nanocrystalline alloy: Role of stress distribution proven by direct X-ray measurements

• FeCrSiBNbCu ribbons were studied after conventional or stress annealing.
• No significant difference of crystallite size and no texture were found.
• For conventionally annealed samples isotropic stress distribution was observed.
• For stress annealed samples the anisotropic stress distribution was evident.
• Stress tensor measurements by X-ray technique is a powerful non-destructive tool.

Fe73.5−xCrxSi13.5B9Nb3Cu1 (x = 1, 2, and 3) amorphous ribbons were prepared by single roller rapid quenching technique. Both conventional and stress annealing at 520 °C for 2 h at the value of the specific load of 150 MPa resulted in the formation of a nanocrystalline structure with average grain size about 13 nm. No significant differences in crystallite size were observed for all samples under consideration. The crystallite orientations were practically isotropic indicating no texture in the samples of all types. For all conventionally annealed ribbons a longitudinal effective magnetic anisotropy with an easy magnetization axis parallel to the ribbon axis was observed. For all stress annealed ribbons a transverse induced magnetic anisotropy with the anisotropy constant value of about 1800 ± 50 J/m3 was evident. Induced magnetic anisotropy features in FeCrSiBNbCu nanocrystalline alloy, namely an importance of the stress distribution was proven by direct X-ray measurements. A very good correlation between the induced magnetic anisotropy constant values and anisotropic stress distribution was observed.

Stress tensor measurements by X-ray technique is a powerful non-destructive tool for investigating structural peculiarities of nanocrystalline soft ferromagnets.Figure optionsDownload as PowerPoint slide