Internal friction in melt spun Nd60Fe30Al10 magnetic nanostructures

H. R. SALVA, , ,; S. E. URRETA; L. M. FABIETTI; A. A. GHILARDUCCI

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

ELSEVIER SCIENCE SA

Lugar: AMSTERDAM; Año: 2009 vol. 521 p. 213 - 216

0921-5093

Nanostructured Nd60Fe30Al10 magnetic alloys were melt spun at tangential wheel speeds of 5 m/s (V5) and 20 m/s (V20). The damping and the dynamic elastic modulus were measured in an automated subresonant forced pendulum in both modes: at fixed frequencies between 0.1 and 1Hz [150¨C480 K], and at constant temperature, varying the frequency between 1 10−3 and 10 Hz, always keeping constant excitation. The magnetic properties were characterized by M¨CH loops and by magnetization vs. temperature measurements in the same temperature range. Ferromagnetic ordering of the Fe-rich phase was observed at 460 and 410K for samples V5 and V20,respectively. After several thermal cycles between 290 and 150K virgin samples showed a sharp relaxation peak at 210K (1 Hz) and a broad one at about 270K (1 Hz), associated to apara-antiferromagnetic transition in the Nd-rich phase. The high temperature internal friction spectra at 1 Hz show an internal friction peak at T ¡Ý500K. No visible changes in the IF near the Curie temperatures are found, but there are large anomalies in the dynamic modulus in the temperature range between the two transition temperatures, that of the Fe-rich mu-like phase and the one of the Nd-rich delta-like phase. These anomalies are significantly affected by the application of a small magnetic field (24 mT) while no changes in the IF are observed