The Structural Relaxation and its Influence on High Field Magnetization Processes

Abstract

In this paper the results of the structural and magnetic investigation of Fe 61 Co 10 Y 8 Zr 1 B 20 alloy after solidification and isothermal annealing was presented. The isothermical annealing was carried out at 700 K for 1 h and 770 K for 3.5 h. For the structural investigation was performed by X-ray diffractometer equipped with a copper lamp. The results of (XRD) measurements showed the material in the state after the solidification and heat treatment is amorphous. Static hysteresis loops and initial magnetization curve was measured using vibrating magnetometer (VSM). The quality and quantity of structural defects in the sample after heat treatment was determined by indirect method using analyze the initial magnetization curve in accordance with the theory of Kronmüllera. These studies have shown that the annealing process has big influence to change significantly quantity of defects in amorphous structure as a result, there are changes of magnetic parameters such as saturation magnetization and field µ 0 M s coercivity H c .

Analysis of the Thermal and Magnetic Properties of Amorphous Ribbons of Fe_{61}Co_{10}B_{20}Y_8Me_1 (where Me~=~W, Zr, Nb, Mo)

“…As has been shown in [6,7,11], for the investigated alloy compositions, it is possible to obtain bulk amorphous alloys -despite the narrow value of ∆T x observed for these alloys. This is quite important because it stresses that, in the process of designing the chemical composition for bulk amorphous alloys, the results of investigations performed on samples in the form of ribbons should not be decisive as they are made with totally different parameters.…”

“…Element Nb does not generate nanocrystalline structure (and as a result an increase in the saturation magnetisation and decrease in the coercivity). This behaviour regarding H c could be rather observed in the case of the addition of Zr, which in small quantities causes an increase in the value of the stiffness parameter of the spin wave D spf [7].…”

“…These minor changes in alloy composition have a relatively major influence on the values of the saturation magnetisation and the coercivity. While the changes in the magnetisation are relatively easy to explain [6,7,11], the sudden increase in the coercivity for the samples where Me=Nb and Mo, is quite complicated. The regions with varying density hinder the free movement of the domain walls and therefore the increase in the coercive field must be taken into account.…”

“…melt spinning). Using this method, it is possible to obtain a solid sample in the form of a ribbon, with a thickness of several µm to several dozens µm [6,7]. Achievements made using this method have substantially widened the range of potential applications for this class of materials.…”

Curie Temperature and Microstructural Changes Due to the Heating Treatment of Magnetic Amorphous Materials

“…Alloys magnetic structure and magnetic properties are strongly influenced by a chemical composition and thermal treatment conditions [4][5][6][7]. As the magnetic alloys usually consist not only transition metals atoms but also other atoms with different atomic radii, heating treatment, even at a temperature slightly higher than the ambient temperature [8][9][10].…”