DMS is a diluted magnetic semiconductor, sometimes also called semimagnetic semiconductor. In such a material, small fraction of nonmagnetic cations is replaced by magnetic ions such us Mn, Fe, or Co. For DMSs with sufficiently good optical quality typically it is possible to observe Giant Zeeman effect, 1 or 2 orders of magnitude enhancement of the splitting induced by combination of magnetic field, magnetization, and sp-d exchange interaction. My achievement in this field was observation for the first time Giant Zeeman effect in wide gap semiconductors based on ZnO and GaN. As a consequence, I have shown, that sign of excitonic splittings, so sign effective of p-d exchange integral, is reversed (ferromagnetic) in case of wide gap DMSs, when compared to typical II-VI semiconductors, where it is antiferromagnetic.

"Observation of strong-coupling effects in a diluted magnetic semiconductor Ga1-xFexN", W. Pacuski, P. Kossacki, D. Ferrand, A. Golnik, J. Cibert, M. Wegscheider, A. Navarro-Quezada, A. Bonanni, M. Kiecana, M. Sawicki, T. Dietl, Phys. Rev. Lett. 100, 037204 (2008).

"Effect of the s,p-d exchange interaction on the excitons in (Zn,Co)O epilayers", W. Pacuski, D. Ferrand, J. Cibert, C. Deparis, J. A. Gaj, P. Kossacki, C. Morhain, Phys. Rev. B 73, 035214 (2006).

"Magneto-optical properties of the diluted magnetic semiconductor p-type ZnMnO", E. Przeździecka, E. Kamińska, M. Kiecana, M. Sawicki, Ł. Kłopotowski, W. Pacuski, J. Kossut, Solid State Commun. 139, 541 (2006).

"Excitonic giant Zeeman effect in GaN:Mn3+", W. Pacuski, D. Ferrand, J. Cibert, J. A. Gaj, A. Golnik, P. Kossacki, S. Marcet, E. Sarigiannidou, H. Mariette, Phys. Rev. B 76, 165304 (2007).

Summary and review on spectroscopy of wide gap DMSs is now a single author chapter (number 2) in a textbook on DMS

"Optical Spectroscopy of Wide-Gap Diluted Magnetic Semiconductors", W. Pacuski, chapter in Introduction to the Physics of Diluted Magnetic Semiconductors edited by Jan A. Gaj and Jacek Kossut, Springer Series in Materials Science Vol. 144, Pp. 37-63 (2010).

and in my PhD thesis

"Optical spectroscopy of wide gap diluted magnetic semiconductors based on ZnO and GaN", W. Pacuski, PhD Thesis (2008).

I had also pleasure to participate in further development of this field,

"Influence of s,p-d and s-p exchange couplings on exciton splitting in (Zn,Mn)O", W. Pacuski, J. Suffczynski, P. Osewski, P. Kossacki, A. Golnik, J. A. Gaj, C. Deparis, C. Morhain, E. Chikoidze, Y. Dumont, D. Ferrand, J. Cibert, T. Dietl, Phys. Rev. B 84, 035214 (2011).

"Effects of s,p-d and s-p exchange interactions probed by exciton magnetospectroscopy in (Ga,Mn)N", J. Suffczyński, A. Grois, W. Pacuski, A. Golnik, J. A. Gaj, A. Navarro-Quezada, B. Faina, T. Devillers, A. Bonanni Phys. Rev. B 83, 094421 (2011).

"Relation between exciton splittings, magnetic circular dichroism, and magnetization in wurtzite (Ga,Fe)N" J.-G. Rousset, J. Papierska, W. Pacuski, A. Golnik, M. Nawrocki, W. Stefanowicz, S. Stefanowicz, M. Sawicki, R. Jakieła, T. Dietl, A. Navarro-Quezada, B. Faina, T. Li, A. Bonanni, J. Suffczyński Phys. Rev. B 88, 115208 (2013).

"Fe dopant in ZnO: 2+ vs. 3+ valency and ion-carrier s,p-d exchange interaction", J. Papierska, A. Ciechan, P. Bogusławski, M. Boshta, M. M. Gomaa, E. Chikoidze, Y. Dumont, A. Drabińska, H. Przybylińska, A. Gardias, J. Szczytko, A. Twardowski, M. Tokarczyk, G. Kowalski, B. Witkowski, K. Sawicki, W. Pacuski, M. Nawrocki, J. Suffczyński, Phys. Rev. B 94, 224414 (2016).

Importantly, I have been never growing wide gap DMSs, all excellent samples used for above research have been delivered by French, Austrian, Polish, and Egyptian co-workers listed in the author list.

My present activity in this field is adding magnetic ions to nanostructres (QDs, QWs), microstructres (e.g. photonic), and 2D materials rather than to classical semiconductors.