Magnetoresistance studies in Al70Pd20+xMn10−x (x=0, 1) icosahedral quasicrystals

Dominance of magnetic scattering in the electrical-transport of Al70.5Pd22Mn7.5 icosahedral quasicrystal

“…The pre-minimum slope (slope of the curve much above T min ) is 0.45 X À1 cm À1 K À1 where as the post-minimum slope (slope of the curve much below T min ) is 2.838 X À1 cm À1 K À1 , which is much larger ($6 times) as compared to the pre-minimum slope. The occurrence of the minimum is in accordance with the earlier reports [8][9][10]13] and also recently by us [25,26]. It can be observed that zero field r-T data shows no signature of maxima, but with the application of 8-T field, a r-T maximum appears at $6 K. A magnified view of the same is shown in the inset of Fig.…”

“…The Kondo effect like signature has also been observed through tunneling spectroscopy measurement [24]. Only recently we have shown [25,26] that the occurrence of maxima and minima in the r-T variation of i-Al-Pd-Mn quasicrystals in the entire studied temperature regime, can be explained quite well by QIEs with e-ph scattering as the inelastic scattering mechanism and Kondo like spin-flip scattering as the random dephasing mechanism.…”

“…Our earlier investigations [25,26] indicate that the origin of this discrepancy perhaps lies in the concentration of magnetic moments present in the sample. To investigate this discrepancy and to further confirm our results described in Refs.…”

“…The observed maxima in the in-field r-T data is similar to that of the zero field r-T data for the samples with higher concentration of Mn viz. Al 70 Pd 20 Mn 10 [25,26]. For comparison, a magnified and properly normalized, low-temperature regimes of the curves are shown in Fig.…”

“…To investigate this discrepancy and to further confirm our results described in Refs. [25,26], in the present study we have selected a poly grain i-Al-Pd-Mn quasicrystal with composition Al 70.5 Pd 22 Mn 7.5 , which shows only conductivity minima and has very low moment concentration like in case of single grain i-Al-Pd-Mn quasicrystals. We have carried out r-T, magneto-resistance and magnetic measurements on this poly grain Al 70.5 Pd 22 Mn 7.5 icosahedral quasicrystal.…”