Fig. 1: Membrane design and characterization.
From: Spatially reconfigurable antiferromagnetic states in topologically rich free-standing nanomembranes
a, Free-standing membranes are prepared by the selective water etching of SAO (yellow), followed by the direct/indirect transfer of membranes (orange) onto desired silicon (Si) or silicon nitride (Si3N4) supports (blue). Indirect transfer requires an intermediate support such as PMMA (purple) to hold the membranes after water etching. For type-C membranes, a buffer layer made of LAO (green) and ultrathin STO (grey) was also grown (Methods). Layer thickness is not to scale. b, Large-area optical image of a buffered α-Fe2O3 membrane transferred onto Si. Scale bar, 1 mm. c, XRD (2θ–ω scans) of as-grown α-Fe2O3|LAO|STO|SAO film on an STO substrate (grey curve) and detached α-Fe2O3|LAO|STO membrane on a SiO2/Si substrate (orange curve). The out-of-plane (006) Bragg peak of α-Fe2O3 lies in the proximity of the (111) LAO buffer and (111) STO substrate peaks. The STO layer in the buffer is too thin to contribute a sizable signal in the detached sample. The inset displays the rocking curve (ω scan) of the detached membrane, exhibiting a full-width at half-maximum of ∼1.1°. d,e, SAED patterns of free-standing unbuffered (type-B) (d) and buffered (type-C) (e) α-Fe2O3 membranes obtained with an electron beam incident along the crystallographic c axis. f, Simulated SAED pattern of the type-C membrane (Methods) corresponding to the pattern in e. The simulation confirms that the satellite peaks in e emerge due to a lattice-mismatch moiré pattern24,25, resulting from the electron-beam interference across α-Fe2O3 and LAO lattices in the buffered membrane.
