Events

Department of Magnetic Reseach Seminar

Single ion magnetic anisotropy of GaN doped with Mn: from paramagnetic GaN:Mn to magnetically percolating dilute (Ga,Mn)N

dr Katarzyna Gas

Instytut Fizyki PAN w Warszawie

Seminarium odbędzie się zdalnie w aplikacji Microsoft Teams. W celu wzięcia udziału w wydarzeniu należy dołączyć do zespołu Seminarium OBM. Można do niego dołączyć na stałe przy użyciu kodu dostępu ol7omod (dotyczy to osób posiadających konto w domenie intibs.pl, pozostałe osoby proszę o kontakt z prof. dr. hab.Adamem Pikulem, prof. INTiBS PAN ())

The seminar will be held remotely in the Microsoft Teams application. In order to participate in the event, you must join the Seminarium OBM team. You can join it permanently using the access code ol7omod (this applies to people with an account in the intibs.pl domain, other people please contact Prof. Adam Pikul , Prof. INTiBS PAN ())

Abstract:

GaN enriched with Mn constitutes worthwhile material system whose magnetic characteristics are set by the d-level occupancy of the Mn ions in wurtzite GaN matrix. Basing on the results of magnetometry performed in a wide temperature range (down to 0.5 K) on industrial quality GaN:Mn crystals (insulating bulk substrates grown by Halide Vapour Phase Epitaxy method) I will re-visit the crystal field model and show that, aided by EPR results, an accurate spin counting of Mn3+ and Mn2+ species is possible. This combination of methods constitutes a unique and indispensable characterization tool for these commercially important crystals. Next, I will proceed to more Mn-concentrated epitaxial (Ga,Mn)N layers with Mn contents approaching 10%. Here, superexchange-mediated ferromagnetism develops at the low end of cryogenic temperatures. The magnetic anisotropy of such systems will be discussed and a possibility of its control by epitaxial strain will be presented.

This work has been supported by the National Science Centre, Poland through OPUS (DEC-2018/31/B/ST3/03438) grant