Monitoring antiferromagnetism via angle-resolved Auger photoelectron coincidence spectroscopy: The case of NiO/Ag(001)

• Published in: Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2013-09, Vol.88 (9), Article 094403
• Main Authors: Gotter, R., Sbroscia, M., Caminale, M., Vaidya, S. R., Perfetto, E., Moroni, R., Bisio, F., Iacobucci, S., Di Filippo, G., Offi, F., Ruocco, A., Stefani, G., Mattera, L., Cini, M.
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Auger electron spectroscopy; Augers; Line shape; Mathematical models; Neel temperature; Photoelectrons; Spectroscopy
• ISSN: 1098-0121; 1550-235X
• DOI: 10.1103/PhysRevB.88.094403

Spin selectivity in angle-resolved Auger photoelectron coincidence spectroscopy (AR-APECS) is used to probe electronic structure in antiferromagnetic thin films. In particular, exploiting the AR-APECS capability to discriminate Auger electron emission events characterized by a different spin of the ion in its final state, a sharp multiplet structure in the Ni MVV Auger line shape of NiO/Ag(001) thin films is measured below the critical Neel temperature. The assignment of multiplet terms follows from a close comparison of the experimental AR-APECS line shapes with the predictions based on semiempirical calculations on a cluster model and an open-band extension of the Cini-Sawatzky approach. In analogy to CoO, also in NiO, above the Neel temperature a more featureless Auger spectrum appears and AR-APECS does not disentangle anymore high-spin and low-spin contributions to the total Auger intensity. Such a behavior, which seems to be a general result for metal oxide antiferromagnetic systems, is discussed.