Study of Ferrites Using X-Ray Photoelectron Spectroscopy Neha, Sandeep Kumar, Hee Kyoung Kang, Weon Cheol Lim, Sangsul Lee, et al. Chemistryselect, 2026 X‐ray photoelectron spectroscopy (XPS) in ferrites (MFe 2 O 4 ; M is divalent transition metal (TM) ion) materials is capable to differentiate between chemical states with the help of intensive investigation of Fe 2p, and M 2p spectra, particularly through splitting into their components, detecting chemical shifts, and shake‐up satellites. Therefore, it could shed light on the behavior of Fe 2+ /Fe 3+ , M 2+ /M 3+ , and even partially filled site occupancies. The binding energy of ions is influenced by several factors, such as average ligand electronegativity, metal‐to‐charge transfer, initial state effect, screening effect and relaxation effect that elucidate the role of the surrounding of ions to be probed. Hence, identification of cations in different surroundings is another feature of XPS. Thus, detailed deconvolution of Fe and other metal core‐level spectra of ferrites can provide insights into the cation inversion, an important factor that directly governs the performance of ferrite‐based devices in spintronics, catalysis, and energy storage. Hence, XPS is not just an analytical tool that can bring the oxidation states into consideration, but a quantitative probe that can clarify cation‐inversion profiles and site occupancy. Thus, this review article summarizes the extensive XPS studies on ferrites, focusing mainly on spinel ferrite systems and doped ferrites.
Angle Dependent X-Ray Absorption Spectroscopy for Investigation of Irradiation Induced Effects in MgO Single Crystals Jitendra Pal Singh, Weon Cheol Lim, Anjali, Manish Kumar, Sanjeev Gautam, et al. X Ray Spectrometry, 2026 Present work investigated the ion irradiation‐induced effects in MgO single crystals using angle dependent X‐ray absorption spectroscopy. MgO single crystals were irradiated using 100 MeV O7+ ions at fluences of 1 × 1011, 1 × 1012, and 1 × 1013 ions/cm2. X‐ray diffraction study showed the presence of the same crystalline structure in the pristine and irradiated counterparts. Variation of X‐ray intensities with ion fluence exhibited onsets of crystalline disorder, which were supported by the variation of lattice parameter with fluence. This behavior is further confirmed by the behavior of the local atomic distortion parameter estimated from Mg K‐edge near edge X‐ray absorption fine structure (NEXAFS) measurements. Further, angle dependent NEXAFS measurements revealed the onsets of slight distortion in atomic structure. These effects were attributed to the dominant electronic excitation in the ion irradiated MgO single crystals.
IMPACT OF HEATING/COOLING RATE ON THE POST-DEPOSITION ANNEALING OF LLZO THIN FILMS WEON CHEOL LIM, SO HEE KIM, ADITYA SHARMA, SANGSUL LEE, HYUN-JOON SHIN, et al. Surface Review and Letters, 2026 This study reports the deposition of garnet-structured lithium lanthanum zirconate (LLZO) thin films using radio frequency (RF) sputtering on glass substrates by varying the heating/cooling rate. Deposition was carried out at a sputtering power of 70 W for 30 min under Ar environment. As-deposited films were annealed at 500°C at different heating/cooling rates (1.5, 6 and [Formula: see text]C/min). It was observed that these films were amorphous in nature and no crystalline phase was reported despite the change in heating/cooling rates. Thickness and compositions of these films were estimated using Rutherford backscattering spectroscopy (RBS) measurements. Thicknesses of as-deposited films were 110[Formula: see text]nm and reduced to 90[Formula: see text]nm on annealing at different heating/cooling rates, suggesting intermixing at the interface. This intermixing phenomenon, observed at the interfaces of the LLZO thin film, suggests potential interactions or diffusion processes during the annealing process.
Precise dopant detection and transport properties of boron ion-implanted silicon solar cells Monika Verma, Sanjeev Gautam, Bibek Ranjan Satapathy, Weon Cheol Lim, Ram Charan Meena, et al. Rsc Advances, 2025 Boron implantation into n-type Si(100) forms p–n junction, confirmed by XPS, and enhanced electrical performance, highlighting its potential for photovoltaic applications.
Ion implantation in ferrites Aditya Sharma, Ksh. Devarani Devi, Weon C. Lim, Keun Hwa Chae Ferrite Nanostructured Magnetic Materials Technologies and Applications, 2023
Progress report of the innovated KIST ion beam facility Joonkon Kim, John A. Eliades, Byung-Yong Yu, Weon Cheol Lim, Keun Hwa Chae, et al. Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms, 2017
