Origins of coercivity in the amorphous alloy Nd-Fe-Al

Results obtained from detailed studies of the microstructure and devitrific ation behavior, as revealed by advanced electron micrsocopy and synchrotron x-ray diffraction techniques, were compared with magnetic and thermal anal ysis characterization to obtain insight into the appreciable coercivity of nominally-amorphous melt-spun ribbon of Nd60-2/3xFe30-1/3xAl10+x (-2 < x < 6.5). The as-spun microstructure consists of an amorphous Nd-rich, magnetic ally-soft matrix with clusters of approximate 1.2 nm diameter that apparent ly confer the hard magnetic properties to the alloy. The clusters are tenta tively identified as sub-unit-cells of Nd6Fe13-xAl1+x, by virtue of their u nique and analogous temperature-dependent magnetic character as well as con siderations of the ternary phase relationships during solidification.