Room temperature ferromagnetism in low dose ion implanted counter-doped Ge:Mn, As
Authors: Donarelli M., Kazakova O., Ortolani L., Morandi V., Impellizzeri G., Priolo F., Passacantando M., Ottaviano L.
Autors Affiliation: Univ Aquila, Dept Phys & Chem Sci, Via Vetoio 10, I-67100 Laquila, Italy; Natl Phys Lab, Hampton Rd, Teddington TW11 0LW, Middx, England; CNR, IMM Bologna, Via Gobetti 101, I-40129 Bologna, Italy; Univ Catania, CNR, IMM, Via Santa Sofia 64, I-95123 Catania, Italy; Univ Catania, Dept Phys & Astron, Via Santa Sofia 64, I-95123 Catania, Italy; CNR, SPIN UOS Aquila, Via Vetoio 10, I-67100 Laquila, Italy; Univ Brescia, Dept Informat Engn, Sensor Lab, Via Branze 38, I-25123 Brescia, Italy; CNR, INO Brescia, Via Branze 38, I-25123 Brescia, Italy
Abstract: We demonstrate room-temperature ferromagnetism in germanium counter-doped with manganese and arsenic at concentrations up to approximately 2.1 x 10(20) at/cm(3): these values are one order of magnitude lower than those at which ferromagnetic behavior has previously been observed. Synthesis proceeded by ion implantation at 513 K followed by annealing in argon at 673 K. High resolution TEM, STEM, and EDX show single-phase diamond cubic material lacking Mn or As precipitates. These findings are consistent with the prediction of Chen et al. that counter-doping with approximately equal concentrations of a single-electron donor permits Mn, a two-electron acceptor, to be incorporated at high enough concentrations to yield a diluted magnetic semiconductor with a Curie temperature above room temperature.
Journal/Review: PHYSICA B-CONDENSED MATTER
Volume: 523 Pages from: 1 to: 5