At the coercivity and the EB in the nanowires happen to be enhanced evidently by forming the Fe@-Fe2 O3 core-shell structure.MethodsThe Fe@-Fe2 O3 nanowires had been synthesized by a reaction between ferrous sulfate and sodium borohydride proposed by Tong et al. previously [23]. All reagents, for instance ferrous sulfate heptahydrate (FeSO4 ?H2 O, AR) and sodium borohydride (NaBH4 , AR), have been obtained from commercial suppliers and were utilised without having any additional purification. A solution of 30.0 mL of 0.70 M NaBH4 was added into 60.0 mL of 0.050 M FeSO4 resolution in a reaction flask while the remedy was vigorously stirred. The reaction mixture was maintained at 60 for as much as 30 min with continuous stirring. The resulting black precipitates had been separated in the option by centrifugation at four,000 rpm for five min, washed quite a few occasions with deionized water and ethanol, and then dried in vacuum at 40 for 24 h to get the as-synthesized item in the Fe@Fe2 O3 nanowire.1783407-55-5 supplier Annealing is definitely the final heat treatment process. The annealing process was performed inside a tube furnace beneath air atmosphere using a six /min heating price, as well as the sample was permitted to annealing at 380 for two, 4, 6, and 8 h, respectively. Soon after the annealing course of action, the sample was cooled down to room-temperature. The cooling price can also be six /min. Structural analysis was performed by X-ray powder diffraction (XRD, D/max-2500) utilizing the Cu Ka radiation ( = 1.Formula of Oxetane-2-carboxylic acid 5406 ?.PMID:33554697 The microstructures, morphologies, plus the elemental distribution from the nanowires had been characterized by transmission electron microscopy (TEM, JEOL 2200F, Akishima-shi, Japan) operating at 200 kV. The magnetic properties were measured by a superconducting quantum interference device magnetometer (MPMS-5S) in magnetic fields up to 50 kOe and more than the temperature selection of five to 300 K.in to the face-centered cubic (fcc) phase of irons. The lattice continual calculated from this XRD pattern is two.862 ? which is very close to the reported data (a = two.860 ? JCPDS file no. 87-0721). Apart from, there is certainly the hexagonal phase of hematite (-Fe2 O3 , JCPDS card no. 33-0664, a = five.036 ?and c = 13.749 ?. The relative intensity of XRD pattern of -Fe2 O3 phase is very low, indicating the very compact quantity of -Fe2 O3 . No additional peaks corresponding to magnetite (Fe3 O4 ) or maghemite ( -Fe2 O3 ) phase are observed inside the as-synthesized sample. For the annealed sample, the relative intensity of the -Fe2 O3 peak increases evidently with escalating TA . On the other hand, for the 8-h annealed sample, it seems some magnetite (Fe3 O4 ) impurity phase (JCPDS card no. 85-1436), which could be as a result of lack of oxygen within the tube furnace for prolonged annealing course of action [24]. The average grain diameters may be estimated by the Scherrer formula. They’re 9.1, 15.7, 18.0, and 20.9 nm for the as-synthesized, 2-h annealed, 4-h annealed, and 6-h annealed samples, respectively. It indicates that the grain size grows up with increasing TA . Nonetheless, for 8-h annealed sample, the concentration of Fe is too low to ensure that the grain size can hardly be estimated.Final results and discussionFigure 1 displays the XRD patterns of your samples with distinctive annealing time TA . It truly is discovered that all patterns are composed of two or 3 phases. For the as-synthesized sample, the diffraction peaks could possibly be mainly indexedFigure 1 X-ray diffraction patterns in the as-synthesized and annealed samples.Cao et al. Nanoscale Research Letters 2013, eight:423 http://nanoscalereslett/content/8/1/Page 3.
