Magnetic properties and magnetoresistance of polycrystalline SrLaCoO4

Polycrystalline SrLaCoO4 with tetragonal K2NiF4 structure were prepared by a solid-state reaction process, and their magnetic properties and magnetoresistance effect were investigated systematically. The paramagnetic–ferromagnetic transition occurred at ∼250 K. The curves of magnetization versus magnetic field at 150, 200 and 273 K showed soft ferromagnetic, super paramagnetic and paramagnetic behavior, respectively. The resistivity increased monotonically with decreasing temperature. The magnetoresistance peak at ∼250 K was due to the ferromagnetic transition. As for the magnetoresistance peak at 12 K, the spin-glass transition at ∼12 K should be responsible for it. In a magnetic field of 5 T, the maximum magnetoresitance (MR) of −18.4% was obtained at 12 K.