Some Thermomagnetic and Mechanical Properties of Amorphous Fe75Zr4Ti3Cu1B17 Ribbons

The microstructure, revealed by X-ray diffraction and transmission Mössbauer spectroscopy, magnetization versus temperature, external magnetizing field induction and mechanical hardness of the as-quenched Fe75Zr4Ti3Cu1B17 amorphous alloy with two refractory metals (Zr, Ti) have been measured. The X-ray diffraction is consistent with the Mössbauer spectra and is characteristic of a single-phase amorphous ferromagnet. The Curie point of the alloy is about 455 K, and the peak value of the isothermal magnetic entropy change, derived from the magnetization versus external magnetizing field induction curves, equals 1.7 J·kg−1·K−1. The refrigerant capacity of this alloy exhibits the linear dependence on the maximum magnetizing induction (Bm) and reaches a value of 110 J·kg−1 at Bm = 2 T. The average value of the instrumental hardness (HVIT) is about 14.5 GPa and is superior to other crystalline Fe-based metallic materials measured under the same conditions. HVIT does not change drastically, and the only statistically acceptable changes are visibly proving the single-phase character of the material.

Эффективное возбуждение магнитоэлектрического эффекта в структуре ферромагнетик-пьезоэлектрик током через магнитный слой

The effective excitation of the magnetoelectric effect in a planar structure amorphous ferromagnet – piezoelectric lead zirconate titanate by alternating current flowing through the magnetic layer was demonstrated. Due to orientation of the exciting magnetic field perpendicular to the constant field and absence of demagnetization, the structure generates even voltage harmonics with efficiency, several times higher than the efficiency of excitation of the effect by volume coils. It was shown that the amplitude of the second harmonic is proportional to the piezomagnetic coefficient of the magnetic layer,increases quadratically with the amplitude of the current and decreases inversely with the biasing magnetic field

Influence of hydrogenation and mechanical grinding on the structural and ferromagnetic properties of GdFeSi

Hydrogen insertion into GdFeSi induces (i) a structural transition from a tetragonal CeFeSi-type to a tetragonal ZrCuSiAs-type, (ii) an anisotropic expansion of the unit cell parameters because the a parameter decreases, whereas the c parameter increases, and (iii) a decrease in Curie temperature from 121 to 20 K. On the contrary, an amorphous ferromagnet (TC = 65 K) is obtained by mechanical grinding of GdFeSi. The three compounds (GdFeSi, GdFeSiH, and amorphous GdFeSi) were investigated by 57Fe Mössbauer spectroscopy. At 4.2 K, this study has revealed that the magnetically ordered Gd substructure produces a small transferred hyperfine magnetic field at the 57Fe nucleus.