Synthesis and Magnetostrictive Properties of High-Pr Content  ${\rm Sm}_{1-x}{\rm Pr}_{x}{\rm Fe}_{1.9}$ Cubic Laves Alloys
Polycrystalline Sm<sub>1-</sub><i>x</i>Pr<i>x</i>Fe<sub>1.9</sub> (0.4 ≤ <i>x</i> ≤ 1.0) magnetostrictive alloys were synthesized by arc-melting and subsequent high-pressure annealing. Measurements of x-ray diffraction, magnetization, and magnetostriction were performed on the alloys. Due to the effects of high-pressure, the alloys are stabilized in cubic Laves phase with MgCu<sub>2</sub>-type structure. The Curie temperature of the cubic Laves phase decreases linearly with the increase of <i>x</i>, which can be associated with the decreasing strength of 3<i>d</i>-4<i>f</i> coupling. With increasing <i>x</i> , the anisotropy of the alloys first decreases to a minimum at <i>x</i> = 0.6 and then increases. The magnetostriction of Sm<sub>1-</sub><i>x</i>Pr<i>x</i>Fe<sub>1.9</sub> changes signs from negative into a positive at <i>x</i> = 0.6 . The saturation magnetostriction increases with increasing <i>x</i>, while the sample with <i>x</i> = 0.9 shows a peak at low magnetic fields.
Structure, thermal stability and magnetostrictive properties of PrFex (1.5 ≤ x ≤ 3.0) alloys
Abstract Polycrystalline alloys PrFex (x = 1.5, x = 1.8, x = 1.9, x = 2.0, x = 3.0) have been prepared by arc-melting and subsequent high-pressure synthesis method. Their structure, thermal stability, easy magnetization direction and magnetostriction are investigated. Almost single Laves phase (MgCu2-type) is found in sample with x = 1.9. Samples with x = 2.0, x = 3.0 consist of PrFe1.9 phase with MgCu2-type cubic structure and α-Fe phase. The Curie temperature (238 °C) and the decomposed temperature (408 °C) of PrFe1.9 alloys are derived from M–T curves. The easy magnetization direction of PrFe1.9 Laves phase lies along [1 1 1] axis at room temperature which is verified by Mossbauer spectrum. Furthermore, PrFe1.9 alloy shows a large magnetostriction λ|| – λ⊥ = 1081 × 10−6 at a magnetic field of 13 kOe.
Ferrimagnetism in SmFe2
Abstract Magnetization measurements of polycrystalline SmFe 2 are interpreted in terms of a ferrimagnetic coupling between the Sm +3 and iron moments. A sign reversal of 〈 S z 〉 relative to 〈 L z + S z 〉 is obtained by single-ion crystal-field calculations of the Sm +3 moment.