Magnetic order in the lamellar compounds La1−Sr1+CoO4 (0⩽x⩽0.4)

Abstract We have studied the AC and DC magnetic properties of the lamellar compounds La 1− x Sr 1+ x CoO 4 (0⩽ x ⩽0.4). These materials are found to evolve towards an anomalous “cluster-glass”-like behaviour as x increases. The onset of the ferromagnetic order in the bidimensional phases is seen to occur at around 150 K, followed by a blocking process around 125 K. Also, present in the magnetic behaviour of these materials is the signal coming from small intergrowths of a perovskite phase, also detected by TEM, although invisible for powder-X-ray diffraction.