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A One-step, Template-free Synthesis, Characterization, Optical and Magnetic Properties of Zn1−xMnxTe Nanosheets

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journal contribution
posted on 27.01.2009, 00:00 by Sayan Bhattacharyya, D. Zitoun, Y. Estrin, O. Moshe, D. H. Rich, A. Gedanken
The Zn1−xMnxTe nanosheets were synthesized by the one-pot RAPET (reaction under autogenic pressure at elevated temperature) approach. The efficient replacement of Zn by Mn within the Zn1−xMnxTe lattice was confirmed from electron paramagnetic resonance (EPR) experiments. The (111) facets form the main surfaces of the ∼38 nm thick nanosheet structures. Mn catalyzes the formation of a small amount of nanorods (diameter ∼2.6 nm) alongside the nanosheet structures. The magnetic measurements (EPR and SQUID) confirm the +II state of manganese in all the products. Two local environments with strong parallel or antiparallel coupling of the Mn spins exist, specially in the case of Mn:Zn = 0.01 (T1). T1 exhibits a relatively large magnetic moment of 0.12 μB at μ0H = 1.0 T and reflects the contribution of a paramagnetic phase (with antiferromagnetic interactions) and of a ferromagnetic phase. Variable temperature cathodoluminescence measurements were performed for all samples and showed distinct ZnTe near-band edge and Mn-related luminescence. An intense and broad intra-Mn2+ transition at relatively large Mn alloy compositions of 10−15% is further consistent with an efficient incorporation of Mn within the host ZnTe lattice. The template-free formation of the nanosheets and nanorods are explained with the help of controlled experiments. From the technological point of view, the organization of the spintronic nanomaterials into 2D or 3D architectures is important for their assemblage onto a microscopic chip and the Zn1−xMnxTe nanosheets is a major breakthrough toward realization of such functionality.