Journal Article

PUBDB-2025-00286

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Structure-Related Electronic and Magnetic Properties in Ultrathin Epitaxial NixFe$_{3−x}$O$_4$ Films on MgO(001)

Rodewald, J.Extern* ; Thien, J.Extern* ; Ruwisch, K.Extern* ; Pohlmann, T.Extern* ; Hoppe, M.DESY* ; Schmalhorst, J.Extern* ; Küpper, K.Extern* ; Wollschläger, J. (Corresponding author)Extern*

2024
MDPI Basel

This record in other databases:      

Please use a persistent id in citations: doi:10.3390/nano14080694  doi:10.3204/PUBDB-2025-00286

Abstract: Off-stoichiometric NixFe$_{3−x}$O$_4$ ultrathin films (x < 2.1) with varying Ni content x and thickness 16 (±2) nm were grown on MgO(001) by reactive molecular beam epitaxy. Synchrotron-based high-resolution X-ray diffraction measurements reveal vertical compressive strain for all films, resulting from a lateral pseudomorphic adaption of the film to the substrate lattice without any strain relaxation. Complete crystallinity with smooth interfaces and surfaces is obtained independent of the Ni content x. For x < 1 an expected successive conversion from Fe$_3$O$_4$ to NiFe$_2$O$_4$ is observed, whereas local transformation into NiO structures is observed for films with Ni content x > 1. However, angle-resolved hard X-ray photoelectron spectroscopy measurements indicate homogeneous cationic distributions without strictly separated phases independent of the Ni content, while X-ray absorption spectroscopy shows that also for x > 1, not all Fe$^{2+}$ cations are substituted by Ni$^{2+}$ cations. The ferrimagnetic behavior, as observed by superconducting quantum interference device magnetometry, is characterized by decreasing saturation magnetization due to the formation of antiferromagnetic NiO parts.

Note: This research was funded by Deutsche Forschungsgemeinschaft (DFG) grant Nos. KU2321/6-1and WO533/20-1.

---

Contributing Institute(s):

1. FS DOOR-User (FS DOOR-User)
2. PETRA-D (FS-PETRA-D)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)

Experiment(s):

1. PETRA Beamline P08 (PETRA III)
2. PETRA Beamline P09 (PETRA III)

Appears in the scientific report 2024

---

Database coverage:
; ; ; ; Article Processing Charges ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Ebsco Academic Search ; Essential Science Indicators ; Fees ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

---