Structural and magnetic peculiarities of Al86Ni8Sm6 alloy in amorphous, crystalline, and liquid states

Abstract

Magnetic, structural, and thermal characteristics of the Al86Ni8Sm6 alloy in amorphous, crystalline, and liquid states have been studied over a wide temperature range of 4–1900 K. It has been found that the amorphous alloy has a pronounced cluster structure with an average cluster size of 2–3 nm. The crystallization process occurs in four stages and no apparent thermal effect at the glass-transition temperature is observed. The amorphous ribbon has no magnetic order up to 4 K but demonstrates superparamagneic behavior. An analysis of isothermal magnetization curves indicates a possible correlation between structural and magnetically ordered clusters. Anomalous changes in the magnetic susceptibility in the liquid state have been found at temperatures substantially higher than the liquidus temperature; the anomalies indicate structural changes in the melt. The magnetic susceptibility in the amorphous, crystalline, and liquid states was found to be characterized by a high Van Vleck paramagnetic contribution and can be described adequately in terms of the classic Van Vleck theory with allowance for mixed valence effects. The obtained results are interpreted using a concept on the existence of a specific covalent-metallic interaction between aluminum and rare-earth metal atoms.