Delta Doping of Ferromagnetism in Antiferromagnetic Manganite Superlattices

TitleDelta Doping of Ferromagnetism in Antiferromagnetic Manganite Superlattices
Publication TypeJournal Article
Year of Publication2011
AuthorsSantos TS, Kirby BJ, Kumar S, May SJ, Borchers JA, Maranville BB, Zarestky J, Velthuis S, van den Brink J, Bhattacharya A
Journal TitlePhysical Review Letters
Volume107
Pages167202
Date Published10
Type of ArticleArticle
ISBN Number0031-9007
Accession NumberWOS:000296370800016
Keywordsdouble exchange
Abstract

We demonstrate that delta doping can be used to create a dimensionally confined region of metallic ferromagnetism in an antiferromagnetic (AFM) manganite host, without introducing any explicit disorder due to dopants or frustration of spins. Theoretical consideration of these additional carriers shows that they cause a local enhancement of ferromagnetic double exchange with respect to AFM superexchange, resulting in local canting of the AFM spins. This leads to a highly modulated magnetization, as measured by polarized neutron reflectometry. The spatial modulation of the canting is related to the spreading of charge from the doped layer and establishes a fundamental length scale for charge transfer, transformation of orbital occupancy, and magnetic order in these manganites. Furthermore, we confirm the existence of the canted, AFM state as was predicted by de Gennes [Phys. Rev. 118, 141 (1960)] but had remained elusive.

DOI10.1103/PhysRevLett.107.167202
Alternate JournalPhys. Rev. Lett.