Hard magnetic properties of bulk amorphous Nd60Fe20Co10Al10 investigated by SANSPOL

Bulk amorphous Nd60FexCo30 xAl10 alloys have been studied by small angle scattering using polarised neutrons SANSPOL . The field used for the measurements was m0H 2T for temperatures between 6 and 100K and m0H 1T between 300 and 480 K. From the fit of the nuclear scattering curves we found the presence of two Nd rich nanocrystallite contributions. The magnetic scattering curves Ion and Ioff at different temperatures show a change in the intensity sign which is related to the magnetic transitions Tc1 and Tc2 observed in the previous studies. At Tc1 50K the Nd nanoparticles became paramagnetic. As holes in the metastable ferromagnetic phase they act as pinning centers . At temperatures larger than Tc2 500K the ferromagnetic matrix became paramagnetic. SANSPOL measurements confirm the hard magnetic properties of the as cast samples considering a domain wall pinning model. r 2004 Elsevier B.V. All rights reserved. PACS 61.12.Ex; 61.46. W; 75.50.Kj Keywords Small angle neutron scattering; Hard magnetism; Amorphou