R. Żuberek

Saturation magnetostriction of FeZrB(Cu) nanocrystalline alloys

The results of the magnetostriction constants for Fe89Zr7B4 and Fe85Zr7B6Cu2 alloys with different crystalline fractions are reported and interpreted in terms of surface and bulk contributions from α-Fe grains.

Magnetic properties of FeZrB(Cu) amorphous alloys; The effect of boron content

Abstract The composition dependences of the basic magnetic properties indicate that Fe-rich FeZrB(Cu) amorphous alloys show behavior characteristic of Invar material. The critical Fe concentration at which the ferromagnetic order disappears is found to be 98%.

Effect of roughness on the surface anisotropy and magnetostriction of magnetic multilayers

Abstract The effect of interfacial roughness on the effective anisotropy and magnetostriction of the magnetic multilayers has been calculated in frames of dipolar and single-ion approximations. The results indicate that the surface contribution to the effective anisotropy and magnetostriction could become, in some cases, very important.

Magnetostriction and magnetic anisotropy of FeCo/Au multilayers

Abstract The saturation magnetization, magnetic anisotropy and magnetostriction have been studied in FeCo/Au multilayers prepared by molecular beam epitaxy (MBE). Attention is given to the effect of the surfaces and interfaces on the properties of the studied multilayers. On the basis of these measurements the surface anisotropy and surface magnetostriction constants have been determined.

Mechanisms responsible for magnetostriction in heterogeneous magnetic systems

Experimental and theoretical research on magnetoelastic properties of heterogeneous magnetic materials is reviewed. Particular attention is devoted to granular and nanocrystalline systems. It is shown that localisation of magnetoelastic strains at the interface leads to the dependence of effective magnetostriction on the size of magnetic inhomogeneities (radius of grains, thickness of magnetic sublayers, etc.). Several phenomenological models of magnetostriction are presented and analysed in detail.

Tailoring soft and hard magnets by annealing Co-based metallic glass

Abstract Co 67 Fe 4 Mo 2 Si 17 B 11 metallic glass ribbon has been subjected to the isothermal annealing at temperatures in the range 250–600°C so as to produce a series of samples with gradually coarser microstructure. For this series of samples a giant increase of the coercivity, exceeding five orders of magnitude, is observed. It shows a possibility to tailor soft or hard magnets using the same parent material. An abrupt increase of the coercivity occurs in a relatively small range of annealing temperatures between 480 and 520°C, and is mainly due to a strengthening of the pinning effect of the precipitates (fine crystalline structure) on the domain walls. Samples annealed at higher temperatures become fully crystallized. First, the metastable phase(s) is created which decomposes to the stable phases at still higher temperature. Coercivity for fully crystallized samples shows first a narrow plateau and afterwards a gradual decrease of its value with increasing temperature of annealing. Magnetic and microstructural properties of the samples, annealed at various temperatures, were investigated applying a number of complementary techniques including DSC and TGM methods, X-ray diffraction, TEM, strain-modulated FMR spectroscopy as well as conventional magnetic measurements.

Magnetic properties of nanocrystalline Fe73.5Cu1Nb3Si16.5B6

Abstract The correlation between microstructure, saturation magnetostriction constant λ s , coercive field and remanence of Fe 73.5 Cu 1 Nb 3 Si 16.5 B 6 amorphous alloy after annealing for 1 h at 400–720°C was studied. Very soft magnetic behavior corresponds to the low value of | λ s | and was observed for the nanocrystalline material, obtained after annealing at 480–530°C.

Magnetostriction of Fe/Gd multilayers

Abstract Using strain-modulated ferromagnetic resonance method we have measured the magnetostriction constant λ s of Fe/Gd multilayers deposited using rf and dc sputtering. For the samples deposited using rf sputtering the contribution to the effective magnetostriction due to the interdiffusion layers has been observed. Samples grown using dc sputtering are characterized by sharp interfaces with no indication of interdiffusion. In his case the magnetostriction consists of two components: one due to the bulk magnetostriction and another due to the intrinsic surface magnetostriction.

Evolution of the hyperfine and magnetoelastic parameters in the course of crystallization process in niobium-free FINEMET-type alloy

Abstract Room temperature Mossbauer spectrometry, magnetostriction SMFMR technique and magnetic measurements of two-phase nanocrystalline Fe76.5Cu1Si13.5B9 alloy have been carried out in order to study structural and magnetic properties. The composition of both the crystalline grains and the amorphous remainder has been derived for samples subjected to various heat treatments. The observed type of evolution of the effective magnetostriction constant points to the strong relaxation process of internal stresses in the course of the crystallization.

Investigations of magnetostriction in Co0.86Ti0.14 amorphous thin films

Abstract In this paper we report the magnetostriction measurements performed on amorphous Co 0.86 Ti 0.14 soft ferromagnetic thin films exhibiting exceptionally high-magnetic-field induced uniaxial anisotropy. The results of magnetostriction in these films are independent of the pressure of the sputtering gas in contrast with the well-defined maximum in the pressure dependence of the anisotropy constant.