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Thermoelectric Power of Gd4(Co-A)3 Compounds (A = Cu, Pt)

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Abstract:

We report on a comparative study of thermoelectric power measurements (S(T)) in ferrimagnetic Gd4(Co1-xAx)3 compounds with A = Cu, Pt, in the temperature range 8 K – 300 K. Whereas in Gd4Co3 S(T) is always negative, for x > 0 the substitution of Co for Cu/Pt gives rise to the appearance of a low temperature positive maximum in S(T) at around 30 K. Based on our previous study of Gd4(Co1-xCux)3 compounds, we argue that this maximum in S(T) originates from electron-magnon scattering and is sensitive to electron band structure changes resulting from the substitution of Co for Cu/Pt and the accompanying reduction in the ratio between the electron-magnon and the electron-phonon scattering strengths. The decreasing role of Co 3d electrons with the progressive substitution of Co for Cu/Pt, evidenced by a strong reduction in the spin disorder resistivity and the Co magnetic moment, is seen to be crucial for the existence of such low temperature maximum in S(T) for x > 0. It is seen that the substitution of Co for Pt leads to higher values of the amplitude and temperature of the positive maximum in S(T) than the substitution of Co for Cu.

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Periodical:

Materials Science Forum (Volumes 730-732)

Pages:

159-163

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.730-732.159

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Online since:

November 2012

Authors:

Teresa M. Seixas, Manuel A. Salgueiro da Silva, Hans F. Braun, Georg Eska

Keywords:

Electron Band Structure, Gadolinium-Cobalt Compounds, Thermoelectric Power

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© 2013 Trans Tech Publications Ltd. All Rights Reserved

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