MAGNETIC-PROPERTIES OF THE PSEUDO-BINARY INTERMETALLIC COMPOUNDS - HF(FE1-XALX)2

From magnetization measurements in polycrystalline Hf(Fe(1-x)Al(x)) 2 Samples, it was observed that the magnetization is not saturated even at high fields (70 kOe). It is suggested that in Hf(Fe(1-x)Al(x))2, a high anisotropy energy and consequently narrow domain walls exist. Magnetization vs. temperature curves present a different behaviour if the sample is cooled with field (FC) or without (ZFC) field. This difference is applied field dependent and is a maximum in the range 0.45 < x < 0.50. The ZFC curve is irreversible with temperature while FC is reversible. In the intermediate concentration range, the coercive field decreases rapidly with temperature. These behaviour can be explained by domain wall pinning and not by spin or cluster glass effects. In the magnetic phase diagram (T(C) vs. x), two different slopes were found and T(C) vanishes at x = 0.63, approximately. To compare the Hf(Fe(1-x)Al(x))2 and Zr(Fe(1-x)Al(x))2 results, we performed the same measurements on a Zr (Fe0.68Al0.32)2 sample and found a similar irreversibility of ZFC magnetization which has not been detected in the literature.