Helios 660

Organ of Corti explants were dissected at postnatal day 4 (P4) in L-15 medium and fixed with 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.2), supplemented with 2 mM CaCl₂ for 1–2 h at room temperature. For older (P20–120) animals, temporal bones were fixed in 4% formaldehyde for 1 h at room temperature and decalcified in 5% ethylenediaminetetraacetic acid (pH 7.2–7.4) for 3–4 days at 4 °C. After unpeeling cochlear bone and removing the stria vascularis and TM, the cochlear coils were isolated, divided into apical, middle, and basal turns and postfixed with 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.2), supplemented with 2 mM CaCl₂ for 1–2 h at room temperature. Samples were rinsed in 0.1 M cacodylate buffer (pH 7.2) and then in distilled water, dehydrated in an ascending series of ethanol, and critical-point dried from liquid CO₂ (Tousimis Autosamdri 815).
Samples were then mounted on aluminum stubs with carbon conductive tabs and were sputter-coated (EMS 300 T dual head sputter coater) with either 5-nm platinum (for conventional SEM) or 4.0-nm palladium (for immunogold-SEM) as previously described^{19 (link)} and observed in field emission scanning electron microscope (Hitachi S-4800) or focused-ion beam (FIB) scanning electron microscope (FEI Helios 660) using secondary or backscatter electron detectors.

A dual-beam focussed-ion-beam (FIB)/scanning-electron-microscope (FEI Helios 660 with EasyLift™ micromanipulator) was used to fabricate APT specimens. A platinum-based gas injection system was used for specimen protection and attachment. Standard lift-out methodology was used to transfer material wedges from the sample to a micro-tip-array carrier-coupon^{45 (link)}. Specimens were made sharp using standard annular milling methods^{46 (link)} with an additional low-energy milling step (5 kV clean-up)^{47 (link)}. This process was sufficient to remove any FIB-deposited Pt that was used during the lift-out process.

The crystallographic phase and microstructures of ceramics were characterized using X‐ray diffraction (XRD, PANalytical Empyrean) and scanning electron microscopy (FESEM, Apreo) in combination with electron backscatter diffraction (EBSD). The degree of pseudo‐cubic [001] texture was determined from the XRD pattern in 2θ range of 20–60° by Lotgering factor method.^[41] The local microstructure of Eu³⁺ doped PMN‐PT and interface between textured grain and BT template were observed by FEI Titan³ G2 double aberration‐corrected microscope at 300 kV. The STEM images were collected by using a high‐angle annular dark field (HAADF) detector which had a collection angle of 52–253 mrad. EDS elemental maps of the sample were collected by using a SuperX EDS system under STEM mode. The TEM sample was prepared by focused ion beam (FIB, FEI Helios 660) lift‐out technique. The atomic positions in the HRTEM images were determined by using two‐dimensional Gaussian fitting by Atomap software.^[42]

The microstructures of the cross-sectional samples are observed by FEI Titan3 G2 double aberration-corrected microscope at 300 kV. All scanning transmission electron microscope (STEM) images are collected by using a high-angle annular dark field (HAADF) detector which has a collection angle of 52–253 mrad. EDS elemental maps of the sample are collected by using a SuperX EDS system under STEM mode. The electron energy loss spectroscopy (EELS) is performed under STEM mode by using a GIF Quantum 963 system. Thin cross-sectional TEM specimens are prepared by using focused ion beam (FIB, FEI Helios 660) lift-out technique. A thick protective amorphous carbon layer is deposited over the region of interest then Ga+ ions (30 kV then stepped down to 1 kV to avoid ion beam damage to the sample surface) are used in the FIB to make the samples electron transparent. The plane-view TEM (high resolution TEM (HRTEM) imaging, and the corresponding selected area electron diffraction (SAED) patterns) is performed on a FEI Talos F200x TEM at 200 kV.

CoS₂ single crystal formation was confirmed with a pyrite
structure by
powder X-ray diffraction (XRD) using a monochromator’s Co Kα
radiation and the Laue diffraction method. The surface morphology
of the crystal was characterized by scanning electron microscopy (SEM)
(Philips XL30). High resolution transmission electron microscopy (HRTEM)
and energy-dispersive X-ray analysis were carried out by using a JEOL
F200 with an operating voltage of 200 kV. Electron transparent samples
were prepared by the FIB technique using an FEI Helios 660. Resistivity
measurement was conducted on quantum design PPMS via the four-probe method. X-ray photoelectron spectroscopy (XPS) spectra
were obtained from a UHV surface analysis system equipped with a Scienta-200
hemispherical analyzer. Raman spectra studies were carried out by
a customary confocal micro-Raman spectrometer with an unpolarized
HeNe laser (632.8 nm) as the light source.

To check the stacking order for slow-cooled and quenched crystals, we carried out TEM measurements to probe and compare the cross-sections. The quenched crystal was from the same piece of re-quenched crystal post-ARPES measurement (Fig. 3). The crystal was prepared from a slow-cooled crystal that we annealed and quenched post-growth. HAADF-STEM imaging was acquired on an aberration-corrected TEM (FEI, TITAN) at 300 kV. A 25 mrad convergence angle and a 40 mrad inner collection angle is used. The contrast of HAADF images is proportional to Z^γ, where Z is the atomic number and 1.3 < γ < 2. Cross-sectional TEM samples were cut on a dual-beam FIB/SEM (FEI Helios 660), with an ending voltage at 2 keV of the ion beam for final thinning. The image was taken along [100] direction on a slow-cooled sample which was reported to have more stacking fault comparing those quenched sample^{47 (link),48 (link)}. The details can be found in Supplementary Note 1.