Magnetoelastic coupling in DyFe11.4Nb0.6. (October 2020) - Wang, W.Q.
Abstract: The structural and magnetic properties of the rare-earth transition metal compound DyFe11.4 Nb0.6 have been investigated over its magnetically order state by variable temperature high resolution synchrotron x-ray diffraction (85 K - 650 K) together with ac magnetic susceptibility (10 K - 300 K), DC magnetization (300 K - 600 K) and heat capacity (2 K - 300 K) measurements. The magnetic ordering temperature has been determined to be TC = 538(5) K while with decreasing temperature, two spin reorientations have been detected around Tsr1 = 265(±5 K) and Tsr2 = 140(±5) K. The Debye temperature θD = 412(±10) K derived from the specific heat measurements of DyFe11.4 Nb0.6 agrees well with the values reported for related compounds, while the density of states at the Fermi level was found to be N(EF ) = 3.8 ev −1 atom −1 . Refinements of the synchrotron x-ray diffraction patterns indicate the occurrence of magnetoelastic couplings at all three magnetic transitions, the Curie temperature TC and spin reorientation temperatures Tsr1 and Tsr2 . The linear thermal expansion has been determined over the temperature range 85 K - 650 K and substantial magneto-volume effects shown to persist at temperatures up to 596 K, significantly above the Curie temperature. Similarly, the spontaneous volume magnetostriction ω s of DyFe11.4 Nb0.6 extends to 1.17 TC, well above the Curie temperature TC = 538(5) K. The spontaneous volume magnetostriction has the value ω s = 1.08 × 10 −2 at 85 K. The properties of such materials offer potential for applications in functional structures. Highlights: The Debye temperature θD = 412(±10) K and the density of states at the Fermi level N(EF ) = 3.8 ev -1 atom -1 are derived. The occurrence of magnetoelastic couplings at TC, Tsr1 and Tsr2 have been well detected. The spontaneous magnetostriction at 85 K is ωs = 1.08 × 10 -2 .