Nanostructured YbAgCu$_{4}$ for potential cryogenic thermoelectric cooling

We have studied thermoelectric properties of nanostructured YbAgCu$_{4}$ for cryogenic temperature range. Nanostructured YbAgCu$_{4}$ has been prepared using arc melting method followed by ball milling and hot pressing process. Thermal conductivity of the nanostructured samples has been reduced at 42 K by 30-50 {\%} compared to the previously reported value. A high power factor of 131 $\mu $W m$^{-1}$ K$^{-2}$ has been obtained at 22 K. A peak dimensionless figure of merit \textit{ZT} of 0.11 has been achieved at 42 K. With the variation of Cu-Ag composition, the temperature of peak \textit{ZT} can be tuned, which could be useful for the preparation of segmented legs. The method of nanostructuring can be implemented with different heavy fermions for obtaining high power factor with reduced thermal conductivity.