High field (14 T) magneto transport of Sm/PrFeAsO

We report high field magneto transport of Sm/PrFeAsO. Below spin density wave transition (TSDW), the magneto-resistance (MR) of Sm/PrFeAsO is positive and increasing with decreasing temperature. The MR of SmFeAsO is found to be 16%, whereas it is 21.5% in the case of PrFeAsO, at 2.5K under applied magnetic field of 14 Tesla (T). In the case of SmFeAsO, the variation of isothermal MR with field below 20 K is nonlinear at lower magnetic fields (3.5 T). On the other hand, PrFeAsO shows almost linear MR at all temperatures below 20 K. The anomalous behavior of MR being exhibited in PrFeAsO is originated from Dirac cone states. The stronger interplay of Fe and Pr ordered moments is responsible for this distinct behavior. PrFeAsO also shows a hump in resistivity (R-T) with a possible conduction band (FeAs) mediated ordering of Pr moments at around 12 K. However, the same is absent in SmFeAsO even down to 2 K. Our results of high field magneto-transport of up to 14 T brings about clear distinction between ground states of SmFeAsO and PrFeAsO.