Transport properties of single-crystalline Ising magnet SmPt2Si2

The electronic transport properties of a SmPt2Si2 single crystal are measured, in which magnetically disordered (paramagnetic) Sm ions are expected to remain partially in the antiferromagnetically (AFM) ordered state occurring below TI = 5.1 K. In the paramagnetic state, the resistivity exhibits a shallow minimum at ~ 11 K and a pronounced negative magnetoresistance, suggesting the occurrence of the Kondo effect and/or AFM short-range ordering. Below TI, the resistivity increases sharply, indicating a decrease in the carrier density caused by a superzone gap formation associated with the AFM transition. As regards the Hall effect, the extraordinary component is negligibly smaller than the normal component. The positive sign of the normal Hall coefficient indicates that the hole Fermi surfaces dominate the electrical transport properties. The difference in the transport properties of the two ordered phases is discussed.