Fig. 1
From: Atomic resolution electron microscopy in a magnetic field free environment
Schematic illustration of magnetic objective lens systems for atomic-resolution TEMs/STEMs. a Schematic cross section of a conventional magnetic objective lens. Samples (shown as a purple disk) are placed between the upper and lower polepieces (in gold color). b Schematic illustration showing the z-component magnetic field (Bz) distribution across the upper and lower polepieces when we excite the magnetic objective lens system. The maximum Bz is found near the sample position. c Schematic cross section of the new magnetic field-free objective lens system developed in this study. This lens system is composed of two round lenses, and samples are placed in between the FOL and the BOL lenses. The polepieces and coils of the FOL and BOL are exactly in the mirror symmetric configuration with respect to the sample plane, but the polarities of their excitations are opposite, resulting in an anti-symmetric magnetic field distribution across the sample plane. d Schematic illustration shows the Bz distribution across this new objective lens. The Bz can be canceled out at the sample position, while the strong magnetic field needed for forming an atomic size electron probe can be located as close as possible to the sample plane
