Sperimagnetism in Fe₇₈Er₅B₁₇and Fe₆₄Er₁₉B₁₇metallic glasses: I. Moment values and non-collinear components

Abstract

Magnetization measurements have been made on a Fe64Er19B17 glass, which exhibits ferrimagnetic compensation at Tcomp = 112 K, and polarized beam neutron scattering measurements have been made on Fe78Er5B17 and Fe64Er19B17 glasses to supplement the measurements made earlier on Fe64Er19B17. The magnetization data were analysed with a phenomenological model, to find the magnetic moments and their components needed to interpret the neutron data. Four spin-dependent scattering cross-sections were obtained in absolute units from each neutron experiment, to determine the atomic-scale magnetic structures of the two glasses. The finite spin-flip cross-sections confirmed that these (Fe,Er)83B17 glasses are non-collinear ferrimagnets. The cross-sections were calculated using a model based on random cone arrangements of the magnetic moments. The moment values and the random cone angles were refined in the calculations, which produced good agreement between the calculated curves and the experimental data. The forward limit of the spin-flip cross-sections |∂σ±∓/∂Ω|Q=0 of the Fe64Er19B17 glass which peaked at Tcomp and the temperature variation of the total scattering amplitudes (b∓p∥(Q)) suggested that the random cone angles open fully so that the collinear components p∥(Q) tend to zero at Tcomp. The ferrimagnetic compensation is therefore characterized by an equality of the magnetic sublattices; the reversal of the magnetic structure and a compensated sperimagnetic phase which appears at Tcomp.

Unusual Field Dependence of the Anomalous Hall Effect in Ta/Tb−Fe−Co

“…In the sperimagnetic phase there exists a distribution of magnetic moments within a cone directed along the easy axis, which broadens the phase transitions, and, thus, might be the reason behind an increased temperature range of this firstorder phase transition up to 10 K in the experiment. The sperimagnetism of rare-earth -transition metal compounds has been studied earlier [28][29][30][31][32][33] . To explain qualitatively the observed magnetic behavior, let us consider the following simple model.…”

Sperimagnetic states in amorphous Gd x (FeCo)1-x (0.2 ≤ x ≤ 0.3) alloys: insights from stochastic magnetic anisotropy analysis

“…Our findings indicate that an increase in anisotropy variance corresponds to an increase in the standard deviation of magnetization. These properties can be observed through magnetization measurements and polarized beam neutron scattering [31,32]. The obtained results hold significance for further exploration of sperimagnetic states near the critical line of second-order phase transition and are also important in a scope of equilibrium and dynamic properties of topological magnetic states in films, e.g.…”

“…Presence of such sperimagnetic structure leads to shift of a compensation point on H-T phase diagram [18]. Neutron diffraction measurements can also indicate this type of ordering [31,32].…”

Sperimagnetism in Fe78Er5B17and Fe64Er19B17metallic glasses: II. Collinear components and ferrimagnetic compensation

“…Our studies of the collinear and non-collinear magnetic structures in metallic glasses [1] were described in Part I [2], where it was explained that the non spin-flip neutron scattering crosssections of (Fe,Tb) 83 B 17 glasses had been simulated using a combination of known and derived partial structure factors [3]. The related (Fe,Er) 83 B 17 glass have been shown to be a non-collinear ferrimagnets by a variety of different measurements [4,5,6,7,8], but our preliminary neutron scattering measurements on a Fe 64 Er 19 B 17 glass at 1.5K, 60K and 180K proved to be difficult to interpret [9].…”