Spin Selectivity of Chiral Mesostructured Iron Oxides with Different Magnetisms
Te Bai, Jing Ai, Yingying Duan, Lu Han, Shunai Che
Abstract
Abstract Spin selectivity physically depends on either magnetic materials with strong internal magnetic fields or symmetry‐breaking materials with large spin–orbit coupling (SOC). However, the spin selectivity of symmetry‐breaking magnetic materials is not understood. Herein, the spin selectivity of iron oxides with different magnetisms arising from varying spin alignment is investigated. Chiral mesostructured films of Fe 3 O 4 (CMFFs), γ‐Fe 2 O 3 (CMγFs), and α‐Fe 2 O 3 (CMαFs), which share the same mesostructure, are prepared by a controllable calcination process of chiral mesostructured FeOOH films (CMOFs) grown on the substrate via an amino acid‐induced hydrothermal route. CMFFs and CMγFs with ferrimagnetism exhibit magnetic field‐dependent and simultaneously chirality‐independent magnetic circular dichroism (MCD) signals, while CMαFs with antiferromagnetism exhibit chirality‐dependent, magnetic field‐independent MCD signals. It is speculated that the competitive effect between the spin alignment‐induced and chirality‐induced effective magnetic fields determines the energy splitting of opposite spins in the materials with different magnetisms.