The structural and magnetic characteristics of phase transformations in Tb(Fe1 − x Al x )2 alloys with concentrations x = 0−0.9 have been measured in the temperature range from 90 to 450 K. The temperature dependences of the hyperfine magnetic fields for each of local configurations of the nearest environment of iron atoms upon substitution of aluminum atoms for iron atoms have been found using Mössbauer spectroscopy.

The Nd(Fe0.9Al0.1)2 alloy was synthesized at a high pressure. The crystalline structural characteristics of the alloy were determined. Hyperfine magnetic interactions in the range from 90 to 450 K were investigated using Mössbauer spectroscopy and the temperature dependences of the magnetic characteristics of the alloy were established depending on the configuration of the nearest environment of the iron atom.

The alloys Nd(Fe 1 − x Al x ) 2 (at concentrations x = 0–1) are synthesized under high pressure. The phase composition and crystallographic structural characteristics of the alloys are determined as a function of the concentration x . Mössbauer spectroscopy is used to study hyperfine magnetic interactions in the temperature range from 90 to 400 K. The temperature and concentration dependences of the magnetic characteristics of the alloys are determined.

The Pr(Fe1 − x Al x )2 alloys with concentrations x = 0–1 have been synthesized under a high pressure. The phase composition and lattice parameters (a and c) have been determined as a function of x. The magnetic and Mössbauer measurements have been performed at T = 90–400 K. It has been established that the Curie temperatures of alloys linearly depend on their composition.

The structural transformations and magnetic phase transitions in the quasibinary system Y(Fe 1 − x Al x ) 2 have been investigated by Mössbauer spectroscopy, X-ray diffractometry, and magnetic measurements of polycrystals.

A complex study of the phase composition, atomic and crystalline structure, magnetic properties, and superfine interactions of the Tb0.3Dy0.7Fe2 − x Co x system alloys (x = 0−1.3) has been performed. The synthesized alloys are isotypic with the cubic Laves phase (C15 type), their cell parameter monotonically decreases with an increase in the Co content and, hence, the saturation magnetostriction also does. However, the concentration dependences of the Curie temperature, saturation magnetization, and superfine magnetic field strength measured in the Mössbauer experiment display a nonmonotonic (dome-like) character.

The x-ray structural properties of samples in the CuGa x Al x Fe 2−2 x O 4 ( x = 0−0.7) and CuGa x Al 2 x Fe 2−3 x O 4 ( x = 0−0.5) systems are studied. It is found that magnetic ordering in dilute copper ferrites affects their structural properties. It is concluded that the frustration of magnetic coupling leads to suppression of the cooperative Jahn-Teller effect in dilute copper ferrites with a frustrated magnetic structure.

The investigation of magnetic properties of diluted ferrite NiGa0.7Al0.7Fe0.6O4 is carried out. The anomalous behaviour of spontaneous magnetization σs(T), coercive force Hc(T) and derivative of spontaneous magnetization (dσs/dT)(T) is revealed for the sample with frustrated magnetic structure. It is found that the Mossbauer spectrum is doublet at the temperature T = 295 K of the investigated ferrite. This is proved that the magnetic structure represents clusters formed by short-range magnetic order at the temperature below the Curie temperature TC. © MISM2005. All rights reserved

The first observation of self-oscillations of an ordered magnetic structure is reported. They were detected by the Mössbauer effect in the Tb 0.8 Y 0.2 Fe 2 ferrimagnetic compound and occur with a period of several days. The oscillations were initiated by a single electric-field pulse (∼10 8 kV cm −1 s −1 ). A phenomenological model of the phenomenon is proposed.

The parameters of the magnetic structure near an impurity ion have been measured using the Mössbauer effect at 119Sn impurity nuclei in a Gd single crystal. The local change in the magnetic anisotropy is calculated. The role of the orbital angular momentum of the matrix ion in the local-magnetic-perturbation mechanism in the heavy rare-earth metals series is estimated.