Spin configuration, magnetic and magnetostrictive properties of Tb0.27Dy0.73-xNdxFe2 compounds

Abstract

The polycrystalline Tb0.27Dy0.73-xNdxFe2 Laves phase compounds were prepared at equilibrium conditions and consequent annealing method at high pressure. Their structural, spin configuration, magnetic and magnetostrictive properties were studied. Rietveld refinement analysis of X-ray diffraction (XRD) reveals that the studied compounds possess predominantly the MgCu2-type cubic Laves phase, coexisting with a small amount of hcp-type rare-earth (RE)-rich phase and PuNi3-type REFe3 phase. The magnetization (MS) and Curie temperature (TC) decrease while the lattice parameter increases with the increase in Nd concentration. The direction of easy magnetization (EMD) accompanied by a rhombohedral distortion (λ111) was observed along [111] axis at room temperature (RT). The spin reorientation transition (SRT) occurs at low temperature, which was explained by the two-sublattice model. Based on the experimental results, a detailed phase diagram has been designed for the Tb0.27Dy0.73-xNdxFe2 Laves phase to demonstrate the different spin configurations and crystal structure. The anisotropy compensation between the Nd and Dy sublattices was realized at x = 0.1. The Nd-containing Tb0.27Dy0.63Nd0.1Fe2 Laves phase compound shows large low-field polycrystalline magnetostriction (λS) and large spontaneous magnetostriction coefficient (λ111~1.7 × 10−3), which may make it a good magnetostrictive material. Our results indicate that the substitution of Nd by Dy in Tb0.27Dy0.73Fe2 compounds is beneficial for the improvement of magnetostrictive properties. The present study might be useful to design Nd-based magnetostrictive materials for technological applications.