Stoichiometric and Cu-poor Cu0.95−xMn0.05InSe2 (x = 0-0.20) compounds were synthesized by high-temperature solid-state reactions. The presence of copper vacancies was revealed by Rietveld refinements of combined neutron and X-ray powder diffraction data. The antiferromagnetic interaction was depressed by the copper deficiency, which might be explained as the competition between the antiferromagnetic Mn-Se-Mn super-exchange interaction and the hole-mediated ferromagnetic exchange induced by the copper vacancy. The introduction of copper vacancies was proposed to be a viable route to impart carrier-mediated ferromagnetic exchange in the chalcopyrite-based dilute magnetic semiconductors.

Suppression of Antiferromagnetic Interactions through Cu Vacancies in Mn-Substituted CuInSe2 Chalcopyrites. J.Yao, C.D.Brunetta, J.A.Aitken: Journal of Physics - Condensed Matter, 2012, 24[8], 086006