Optically Induced Magnetization in Metal Halide Perovskite

January 4, 2022
Optically Induced Magnetization in Metal Halide Perovskite
Left: Schematic of the heterostructure with applied field H inducing magnetization in the Co layer, and illumination by circularly polarized laser light. Right: chemical neutron scattering length density (NSLD) near the Co-MAPbBr3 interface is shown in purple. Magnetic scattering length density (MSLD) under illumination by circularly polarized light (green) shows magnetization extending into the perovskite layer that is absent under dark conditions.

Scientific Achievement

It is shown that photoexcitation at room temperature induces near-surface magnetization in a metal halide perovskite beneath a layer of ferromagnetic cobalt.

Significance and Impact

Optical control of magnetism in a heterojunction containing semiconducting perovskite layers opens up a new method of building spin-related optoelectronic devices.

Research Details

  • Spin casting was used to coat a silicon substrate with perovskite methylammonium lead bromide (MAPbBr3), and a heterostructure was built by thermally depositing a layer of Co capped by a layer of Au.
  • Circularly polarized laser light photoexcites orbital magnetic dipoles with the surface of the perovskite, and these couple to the spins at the interface with the ferromagnetic Co layer.
  • In-situ Polarized Neutron Reflectometry (PNR) was used to obtain a chemical and magnetic depth profile, directly showing the existence of optically induced magnetization penetrating several nm into the perovskite surface.

“Optically Induced Static Magnetization in Metal Halide Perovskite for Spin-Related Optoelectronics”

Miaosheng Wang, Hengxing Xu, Ting Wu, Haile Ambaye, Jiajun Qin, Jong Keum, Ilia N. Ivanov, Valeria Lauter, and Bin Hu,

Advanced Science 8, 2004488 (2021). DOI: https://doi.org/10.1002/advs.202004488