Evolution of Magnetism in Sr$_{2-x}$La$_{x}$FeO$_{4 }$ system of compounds at low temperature

We report on the evolution of magnetism at low temperature in two compounds of the Sr$_{2-x}$La$_{x}$FeO$_{4}$ system. Our studies confirmed the room temperature structures of both the compounds that crystallize in the tetragonal K$_{2}$NiF$_{4}$ structure with I4/mmm space group. Both the compounds have antiferromagnetic ordering temperatures above 100K. Low temperature neutron diffraction were taken on the Single Crystal Diffractometer at Los Alamos Neutron Science Center and Intensed Pulsed Neutron Source(IPNS) to gain more insight into the evolution of magnetism below 30K and the nature of transitions evidenced in the previous studies.