Poster presented by Pablo Bobes-Limenes in the International Symposium of Metastable, Amorphous and Nanostructured Materials held in Gijón (Spain) in July 2011.

1. Inverse Wiedemann effect in Fe-Al alloys for
Grupo de Investigación
y Desarrollo de
Materiales Magnéticos torque sensing applications.
P. Bobes-Limenes, J.A. García, J. Carrizo, M. Rivas and J.C. Martínez-García Universidad de Oviedo
Departamento de Física. Universidad de Oviedo. Campus de Viesques, 33203 Gijón, Spain.
This work deals with the inverse Wiedemann effect (IWE) as a method to measure torque using Fe-Al alloys, especially
1
Fe81Al19 alloy which has been reported to have a giant magnetostriction. The influence of several factors has been studied
in order to maximize the sensitivity of the sensor.
300 nm
The alloy under study has been fabricated in our In order to repeat measurements in a quick and precise
laboratory by melt spinning technique. A partially way, an automatic system of experimentation has been
crystallized structure has been obtained as it is shown in designed with very high sensitivity using a stepper motor
TEM and X-ray figures. controlled by a PC.
Before annealing, minimum peak is far from zero
degrees due to internal stresses.
Annealing the ribbon displaces the IWE curve,
correspondingly bringing the minimum peak to zero
degrees.
The characteristics of the current through the ribbon determine the response of the inverse Wiedemann effect.
AMPLITUDE FREQUENCY
Other factor that has been taken into account is the
composition of the ribbon. Measurements have been
done in ribbons with different percentage of aluminum
showing promising results.
Considering the results, it seems that some
compositions could present a huge IWE related
to smaller coercivities.
Hc = 240 kA/m Hc = 132 kA/m Hc = 320 kA/m
Further research will be undertaken in this
direction.
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056) (2006) Edited by C.A. Grimes, E.C. Dickey and M. Pishko