Spin polarisation is found in the centrosymmetric nonferromagnetic crystals, chiral mesostructured NiO films (CMNFs), fabricated through the symmetry‐breaking effect of a chiral molecule. Two levels of chirality were identified: primary nanoflakes with atomically twisted crystal lattices and secondary helical stacking of the nanoflakes. Spin polarisation of the CMNFs was confirmed by chirality‐dependent magnetic‐tip conducting atomic force microscopy (mc‐AFM) and magnetic field‐independent magnetic circular dichroism (MCD). Electron transfer in the symmetry‐breaking electric field was speculated to create chirality‐dependent effective magnetic fields. The asymmetric spin–orbit coupling (SOC) generated by effective magnetic fields selectively modifies the opposite spin motion in the antipodal CMNFs. Our findings provide fundamental insights for directional spin control in unprecedented functional inorganic materials.

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The spin-polarized electrons are of particular interest, which make it highly desirable for transferring and manipulating information when combining spin properties with electronics. [3] The spin of charged particles is the intrinsic magnetic moment and is the essential feature underlying the magnetic properties of matter. Thus, these spinpolarized electrons transfer or transport is usually associated with magnetic materials or depends on the presence of strong magnetic fields. Recently, spin-selective transport in the systems that lack inversion symmetry with a large spin-orbit coupling (SOC) has been proposed. [4,5] As an intrinsic property in all matter, the SOC is remarkably enhanced in inorganic crystals with heavy atoms or in organic compounds with curved carbon systems. [6] The chirality-dependent SOC that acts on the propagating electrons in symmetry-breaking potentials is referred to as Dresselhaus or Rashba effect, [7] and chirality induced spin selectivity (CISS), [4,5,8,9] which could affect the spin current, enantiomeric discrimination, electronic memory, spintronic-based magnetic memory devices, etc. [9,10] In a symmetrybreaking matter, the intrinsic magnetic field that is contributed by the self-magnetization due to the spin alignment acting on the magnetic moment of the electron could produce a magnetization-dependent SOC, which might be a key factor for tuning spin selectivity in addition to the chiral parameter and electron motion. [4,5] However, the effect of intrinsic spin alignment on the spin selectivity of chiral matter has not been understood.Here, iron oxides were chosen as the target materials due to their abundant crystal phases with various magnetisms. [11,12] Among them, highly crystalline Fe 3 O 4 , α-Fe 2 O 3 , and γ-Fe 2 O 3 are known to be stable and have been well studied. Hematite (α-Fe 2 O 3 ) is an antiferromagnetic n-type semiconductor with a bandgap of 2.2 eV. [13] All energy bands in α-Fe 2 O 3 are degenerate because of the spatial inversion symmetry. [14] Magnetite (Fe 3 O 4 ) is a ferrimagnetic half-metallic material [15] and maghemite (γ-Fe 2 O 3 ) is a ferrimagnetic n-type semiconductor with bandgap of 2.2 eV. [16] Both the conduction band and valence band in Fe 3 O 4 and γ-Fe 2 O 3 are nondegenerate because of the exchange interaction. [17] All three iron oxides could be obtained by a controllable calcination process. Thus, various chiral mesostructured iron oxides with identical chiral mesostructures but different magnetisms (see below) were obtained from the same precursor, here, which was chosen for investigating the effect of intrinsic spin alignment on the spin selectivity of chiral matter.

Half-metallic materials are theoretically predicted to be metallic and insulating,w hichh ave not been confirmed experimentally,and the predictions are still in doubt. We report the resistance-chiral anisotropy(R-ChA), i.e., chirality-dependent electrical conductivity,i nc hiral mesostructured Fe 3 O 4 films (CMFFs) grown on the substrates via ah ydrothermal method using amino acids as symmetry-breaking agents.T wo levels of chirality exist in the CMFFs:primary distortion of the crystal lattice forms twisted nanoflakes,a nd secondary helical stacking of nanoflakes forms fan-shaped nanoplates.A t temperatures below3 0K,t he CMFFs exhibited metallic conductivity and insulation for one handedness and the other, respectively.T he chirality-dependent effective magnetic fields were speculated to stabilizet he opposite spin in the antipodal chiral frame,which led to the free transport of electrons in one handedness of the chiral structure and immobility for the other handedness.

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