Spin Orientation Diagrams in Rare Earth Cubic Compounds

Features Peculiar to the Acoustic Properties of Intermetallic SmFe2 in the Spin Reorientation Region

“…Thus the obtained ultrasonic measurement data fully support the results of [2,3,61 as to the existence in the SmFe, compound of two characteristic spin-reorientation transition temperatures. The high-temperature and low-temperature phase transition proceeds apparently as first-order and second-order transition, respectively.…”

“…As indicated in [6] on the basis of Mossbauer experiments, the temperature range in which spin reorientation comes into play is 150 K < T < 200 K. At the same time, X-ray diffraction mesurements of magnetoelastic lattice distortions [2] yield again two critical temperatures, T,, = (160 f 5) K and T,, = (200 Thus the conclusion drawn in [5] is at variance with the data obtained in [2,3,61. In this context, the present paper aims to investigate again the v,(T) and v,(T) relations as well as the temperature dependences of the absorption coefficients of longitudinal a, and transverse a, ultrasonic waves (USWs) for the SmFe, compound, with a view to ascertain in detail the influence of spin reorientation in SmFe, on the acoustic properties of this material.…”

“…structure and should be ranked among ferromagnets exhibiting high anisotropic and magnetoelastic interaction energies [l, 21. In studying the Mossbauer effect in this material [3], it has been found that below the critical temperature T,, = 140 I ( the easy magnetization axis (EMA) is oriented along (1 10)-type crystallographic directions. However, above the other critical temperature, T,, = 240 K, the equilibrium position of the EMA is in (1 11)-type directions; as the temperature is varied in the interval between 140 and 240 K a smooth EMA reorientation from one of the specified crystallographic directions to the other comes about and a (uuv)-type angular phase exists here.…”

Dipolar contributions to magnetic hyperfine fields in ErxY1−xFe2 and TbxY1−xFe2 compounds

“…The experimental results indicate the presence of an enhancement factor which increases the difference of the hyperfine fields beyond the values predicted by assuming a simple magnetic dipolar contribution. This enhancement factor, which is equal to about 1.5 in the present systems, was found to be four times higher in SmBe, [5]. The main contribution to the hyperfine fields H,, acting on the iron nucleus, is attributed to core polarization via the conduction electrons.…”

“…Bowden et al [l] attributed the observed difference in the values of the hyperfine magnetic fields a t inequivalent iron sites to different magnetic dipolar contributions a t these sites. Recent measurements in SmFe, [5] have shown, however, that the measured difference in the values of the hyperfine fields at the inequivalent sites was more than six times greater than could be accounted for by dipolar contributions.…”