Magnetoelastic Coupling in DyFe11.4Nb0.6

The structural and magnetic properties of the rare-earth transition metal compound DyFe11.4Nb0.6 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 T-C = 538(5) K while with decreasing temperature, two spin reorientations have been detected around T-sr1 = 265 (+/- 5 K) and T-sr2 = 140(+/- 5) K. The Debye temperature theta(D) = 412(+/- 10) K derived from the specific heat measurements of DyFe11.4Nb0.6 agrees well with the values reported for related compounds, while the density of states at the Fermi level was found to be N(E-F) = 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 Tsr(1) and Tsr(2). 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 ros of DyFe11.4Nb0.6 extends to 1.17 T-C, well above the Curie temperature T-C = 538(5) K. The spontaneous volume magnetostriction has the value ros = 1.08 x 10(-2) at 85 K. The properties of such materials offer potential for applications in functional structures.