Thermal Stability of Field- and Stress-Induced Anisotropy in Nanocrystalline Fe-Based and Amorphous Co-Based Alloys

Thermal stability of induced magnetic anisotropy (IMA) was studied in a course of subsequentannealings without any external effects for already field- or stress-annealed specimensof the nanocrystalline Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 and amorphous Fe 3 Co 67 Cr 3 Si 15 B 12 alloys. For these alloys the dependence of IMA thermal stability on the magnitude of theIMA constant ( K u ) and temperature of stress-annealing was investigated. For the nanocrystallinealloy thermal stability of field- and stress-induced anisotropy with identical K u was compared. It was shown that nanocrystalline specimens with identical K u values afterfield- or stress-annealing have identical thermal stability of IMA. This can point to asimilarity of the mechanisms of IMA formation after field- or stress-annealings. Thermalstability of stress-induced anisotropy in the nanocrystalline alloy with K u value less than1000 J/m 3 and the amorphous alloy with K u less than 100 J/m 3 depends on the value of K u .For both stress-annealed nanocrystalline and amorphous alloys magnetic anisotropyinduced at higher temperatures is more stable because more long-range and energy-takingprocesses take place at these temperatures.