INVESTIGADORES
FABIETTI Luis Maria Rodolfo
artículos
Título:
Nd60Fe30Al10 Glass Forming Magnetic Alloys: A Mechanical Spectroscopy Study at the 300-560 K Temperature Range
Autor/es:
H. R. SALVA; A. A. GHILARDUCCI; S.E. URRETA; L.M. FABIETTI; J. M. LEVINGSTON
Revista:
DIFFUSION AND DEFECT DATA, SOLID STATE DATA. PART B, SOLID STATE PHENOMENA
Editorial:
Trans Tech Publications
Referencias:
Año: 2012 vol. 184 p. 428 - 433
ISSN:
1012-0394
Resumen:
The ferromagnetic amorphous phase in rapidly solidified
Nd60Fe30Al10 glass forming alloys is investigated in melt
spun ribbons (100 µm thick) and in chill cast cylinders (2 mm diameter). The amorphous
resulting for these two different quenching rates were characterized by their
room temperature hysteresis loops, magnetization
and differential calorimetric measurements in the temperature range 300K-900K. The
mechanical damping was explored in the 300-560 K temperature range, by
measuring the internal friction and the shear modulus in a forced inverted
pendulum operating in the frequency range 0.1-10Hz. Simultaneously, the
electrical resistance of the samples was measured. The internal friction spectra
of both, ribbons and a cylinder, exhibit a local maximum at about 500K, arising
in a relaxation mechanism. After some thermal cycles the peak parameters
stabilize reaching an apparent activation enthalpy of 1.5 eV and a limit
relaxation time τ0 ≈ 0.4-2.5 . 10-17s. In both samples,
the electrical resistance largely decreases during the first heating run to 560K
and remains unchanged during subsequent thermal cycles. No changes in the elastic
modulus or in the damping properties are detected at the Curie temperature of
the alloys.