A potential dilute magnetic semiconductor: Lead-free Cs2AgBi1-xFexBr6 double perovskite

The demand for the increase of information storage density and manipulation speed boosts the intense development of new magnetic materials. Among them, dilute magnetic semiconductors are considered to be promising candidates. Here, we present the doping-induced ferromagnetism in lead-free Cs2AgBiBr6 double perovskite through partly replacing the bismuth atoms with iron, and systematically investigate the influence of doping concentration on the optical and magnetic properties of the crystals. With the increase of iron concentration, the crystal converts from diamagnetism to weak ferromagnetism. Specifically, the one with the highest iron concentration of 1.92% shows magnetic response during the entire temperature region between 3 and 300 K and an effective magnetic moment of 0.46 mu B. The EPR measurement confirms the magnetic isolated state of Fe3+ in the host lattice at room temperature. This work offers a new strategy for the construction of magnetized double perovskites, which is a potential new kind of DMS for the further application of lead-free halide perovskites in the spintronics.