Magnetism and disorder in bcc AlCuFe intermetallics

MARCOS MEYER; LUIS MENDOZA ZELIS; FRANCISCO SANCHEZ

La Plata

Workshop; HFILP 2005 - 35th Anniversary of Hyperfine interactions at La Plata International Workshop; 2005

We present here a systematic study of the structural and magnetic properties of a series of alloys around a central composition Al50Cu20Fe30, obtained by mechanical alloying. The samples have bcc crystalline structure with partial B2 order. Thermal annealing, through differential scanning calorimetry measurements, just removes some defects but do not change the crystalline structure. AC susceptibility measurements show that in spite of their structural similarity these samples have quite different magnetic behaviours. Furthermore, most of the samples shown a complex magnetic evolution with temperature. Some samples have a cluster glass-like behavior at low temperatures and a superparamagnetic-like one at higher temperatures. A model of magnetic clusters originated in composition fluctuations across the alloy is proposed to explain the observed magnetic properties.