Absence of ferromagnetic behaviour in mn implanted ZnO

Bharuth-Ram K, Doyle TB, Adoons V, Ronning C (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Hyperfine Interactions Springer Verlag (Germany)

Book Volume: 243

Article Number: 25

Journal Issue: 1

DOI: 10.1007/s10751-022-01809-y

Abstract

Application of ZnO as a dilute magnetic semiconductor awaits consensus on the source of reported ferromagnetic behaviour in doped ZnO, whether due to dopant-defect interactions or formation of nanoclusters of the magnetic ion dopants. In a contribution to this search, we report on conversion electron Mössbauer Spectroscopy (CEMS) and magnetization studies on single crystal ZnO substrates implanted with Mn ions with energies and fluences designed to give flat implantation profiles with 3 and 7 at% concentration (samples ZnO:Mn1 and ZnO:Mn2). For CEMS measurements, the substrates were also co-implanted with 3.9 × 1015 cm-2, 60 keV 57Fe ions. The CEM spectra of both samples, after annealing at 600oC, and above, show no evidence of ferromagnetic components but are dominated by paramagnetic doublets with isomer shifts consistent with Fe3+. The primary doublet component for both samples have identical values of isomer shifts and quadrupole splittings, thus reflecting the similarity in size and nature of the clusters formed. Magnetic isotherms on the ZnO:Mn1 doped sample are satisfactorily fitted by the Langevin function in the range 5 K < T < 30 K, where the magnetic units are isolated Mn, Fe and defect sites and the system is superparamagnetic. At T = 294 K, a fit to the Langevin fit indicates precipitates/clusters of nano-size dimensions in range where superparamagnetic behaviour is expected.

Involved external institutions

University of KwaZulu-Natal (UKZN) ZA South Africa (ZA) Durban University of Technology (DUT) ZA South Africa (ZA) Friedrich-Schiller-Universität Jena DE Germany (DE)

How to cite

APA:

Bharuth-Ram, K., Doyle, T.B., Adoons, V., & Ronning, C. (2022). Absence of ferromagnetic behaviour in mn implanted ZnO. Hyperfine Interactions, 243(1). https://doi.org/10.1007/s10751-022-01809-y

MLA:

Bharuth-Ram, K., et al. "Absence of ferromagnetic behaviour in mn implanted ZnO." Hyperfine Interactions 243.1 (2022).

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