Formation of two-dimensionally confined superparamagnetic (Mn, Ga)As nanocrystals in high-temperature annealed (Ga, Mn)As/GaAs superlattices
2013 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 25, no 19, 196005- p.Article in journal (Refereed) Published
The annealing-induced formation of (Mn, Ga)As nanocrystals in (Ga, Mn)As/GaAs superlattices was studied by x-ray diffraction, transmission electron microscopy and magnetometry. The superlattice structures with 50 angstrom thick (Ga, Mn) As layers separated by 25, 50 and 100 angstrom thick GaAs spacers were grown by molecular beam epitaxy at low temperature (250 degrees C), and then annealed at high temperatures of 400, 560 and 630 degrees C. The high-temperature annealing causes decomposition to a (Ga, Mn)As ternary alloy and the formation of (Mn, Ga)As nanocrystals inside the GaAs matrix. The nanocrystals are confined in the planes that were formerly occupied by (Ga, Mn)As layers for the up to 560 degrees C annealing and diffuse throughout the GaAs spacer layers at 630 degrees C annealing. The two-dimensionally confined nanocrystals exhibit a superparamagnetic behavior which becomes high-temperature ferromagnetism (similar to 350 K) upon diffusion.
Place, publisher, year, edition, pages
2013. Vol. 25, no 19, 196005- p.
Engineering and Technology
Research subject Engineering Science with specialization in Solid State Physics
IdentifiersURN: urn:nbn:se:uu:diva-200650DOI: 10.1088/0953-8984/25/19/196005ISI: 000318070100027OAI: oai:DiVA.org:uu-200650DiVA: diva2:625057