Transport properties and mangetoresistance of (RE,Sr)2NiO4 (RE=Pr, Nd, Sm and Eu) Original Research Article

We report on the crystal growth and the measurements of resistivity, magnetoresistance and photoemission spectroscopy of (RE,Sr)2NiO4 in the heavily Sr-doped region. Although the in-plane resistivity of the heavily Sr-doped crystals was rather small at room temperature, it increased for several orders of magnitude with decreasing temperature. A large negative magnetoresistance was observed for NdSrNiO4 at low temperature, while only small magnetoresistance was observed for the single crystals of RE=Pr, Sm and Eu. Photoemission spectroscopy measurements revealed a significant influence of the RE 4f states to the electronic structure at relatively low binding energies in PrSrNiO4 and NdSrNiO4.