Spin-Polarized Lasing via Ferromagnetic Spin Filtering in Hybrid Perovskites

Metal halide perovskites are rapidly emerging as a promising platform for spin-polarized lasers. However, the weak Zeeman effect of perovskites makes it challenging to realize the magnetic-field induction and manipulation of spin-polarized lasing. Here we introduce a ferromagnetic spin filtering effect in perovskites to achieve spin-polarized lasing. A composite is designed by incorporating ferromagnetic Fe 3 O 4 nanoparticles into an organic–inorganic hybrid perovskite. Under a magnetic field, the Fe 3 O 4 nanoparticle selectively captures electrons with particular spin from the perovskite, resulting in an effective spin polarization for lasing. The magnetic field direction and strength determine the chirality and circular polarization degree of the spin-polarized perovskite lasing. Furthermore, wavelength-tunable spin-polarized lasers are realized by exploiting the composition-tailored bandgaps of hybrid perovskites. Our work establishes a ferromagnetic spin filtering strategy for spin-polarized perovskite lasers.