Local Structure and Magnetic Characteristics of FINEMET Alloys Substituted by Vanadium

Abstract

Amorphous and nanocrystalline FINEMET-type alloys with vanadium addition up to 7 at% were investigated by the Mössbauer spectroscopy and magnetic methods. The outcomes evidence alterations in grain structure, although the main effect is related to the changes in intergranular phase. This induces diminution of mean hyperfine field, saturation induction and Curie temperature as well as the increase in coercivity.PACS numbers: 75.50.-y, 76.80.+y 1. The subject and methods of the study Nanocrystalline FINEMET• R alloys obtained by controlled annealing of the amorphous precursor and composed of fine grains enclosed in an amorphous matrix are known as excellent soft magnetic materials [1,2]. In order to improve the magnetic properties, various modifications of chemical composition have been proposed for the last decade [3][4][5][6]. In this paper, the substitution of iron atoms by vanadium ones is considered. Previous X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies indicate changes of local structure due to vanadium addition as well as preservation of the nanocrystalline structure with grains sizes of about 15 nm [7]. In this paper, the systematic Mössbauer study is presented, complemented with results of magnetic investigations.The series of Fe 73.5−x V x Cu 1 Nb 3 Si 13.5 B 9 ribbons (x = 1, 3, 5, 7) was manufactured by rapid quenching from the melt. Subsequent annealing for 1 h at (51)

Changes in structure and magnetic hyperfine fields of Finemet alloys, induced by transition elements substitution

“…Mössbauer spectra were numerically analyzed by means of MOSFIT program basing on the Varret method (Teillet and Varret, unpublished). The results were compared with those obtained for Finemet-type alloys, substituted by vanadium and cobalt: (Fe 1− p Co p ) 73.5 Nb 3 Cu 1 Si 13.5 B 9 ( p = 0, 0.1, ..., 0.9), Fe 73.5−z V z Nb 3 Cu 1 Si 13.5 B 9 (z = 1, 3, 5, 7) and fabricated by use of the similar procedure [10,11].…”

“…This causes strong decline of the mean value of MHF related to the amorphous remainder, which is observed for y > 40 at.% of cobalt. Otherwise, in Finemet alloys substituted by vanadium ( [10,11], alloys annealed at 530 • C) the structure of nanocrystallites, stated as Fe(V) 3 Si, is found to be much more stable, what generates nearly constant value of MHF of corresponding subspectrum. It was stated that the replacement of Fe atoms by V ones induces weakening of magnetic interactions inside the amorphous remainder as well as creation and further increase of paramagnetic phase attributed to iron-poor regions of the matrix.…”

Structural and magnetic properties of Fe73.5Cu1Nb3−xTixSi13.5B9 (x≤3) alloys

“…Generally, Nb is considered as an essential composition element to hinder crystal growth [6], resulting in the formation of nanocrystalline ␣-Fe(Si) phase with grain size less than the ferromagnetic correlation length (L ex = 35 nm) [7]. In order to further improve the soft magnetic properties and to reduce the cost of materials, various researches on the substitution effects of Nb by Mo, V, Mn, Cr and Al have been conducted [8][9][10][11][12]. This work attempts to investigate the substituting effects of Ti for Nb in Fe 73.5 Cu 1 Nb 3−x Ti x Si 13.5 B 9 (x = 0, 1, 2, 3) alloys on the crystallization behaviors, microstructure and magnetic properties.…”