Synthesis, characterization and effect of dopant on magnetic hyperthermic efficacy of Gd2O3 nanoparticles

Rare-earth oxides are paramagnetic materials and their high magnetic susceptibility in the bulk makes them potentially promising materials, but the magnetic properties of their nanoparticles remain incompletely characterized. We explore the effect of dopant (Tb3+ and Eu3+) in Gd2O3 host lattice as a heating agent for magnetic hyperthermia application. The structural, optical, and magnetic properties of the pristine, Gd2O3:Tb3+ and Gd2O3:Eu3+ nanocrystals were studied by XRD, HR-TEM, FTIR, and VSM. XRD analysis revealed the presence of mixed phase (cubic and monoclinic) in pristine, and doped Gd2O3 nanoparticles. The morphological information has been observed with the help of HRTEM and the calculated inter-planar spacing is in well agreement with JCPDS data. Particles are nearly spherical and diameter ~15nm, estimated from HRTEM image. FTIR spectroscopic analysis confirms the presence of Gd-O-Gd stretching at 583cm-1 . We confirmed the paramagnetic nature for all samples using VSM analysis. The self-heating capability of prepared samples are investigated by performing the induction heating experiment and it is assessed through calculated SAR and ILP values with help of Box-Lucas fitting model where 10% Tb3+ doped Gd2O3 has maximum values.

Ground Magnetic Surveying and Susceptibility Mapping Across Weathered Basalt Dikes Reveal Soil Creep and Pedoturbation

Ground magnetic survey profiles across a soil-covered and weathered mafic dike in sedimentary host rock not only permit to delineate the strike, width and burial depth of the intrusive basalt sheet, but also reflect the subsurface deformation of its clayey weathering products. We illustrate this finding and its practical geomorphological applicability by an example from the mid-German Heldburg Dike Swarm, where blue- and olive-gray basalt-derived clays inherited not just the dike space previously occupied by the basalt, but also large parts of its magnetic iron minerals and their strong induced and remanent magnetization. Such ductile basaltic “marker soils” deform and move with the surrounding low-magnetic host soils, but remain distinguishable by their contrasting colors and high magnetic susceptibility. Ground magnetic surveys can therefore delineate soil creep distance at meter- and basalt weathering depth at decimeter-precision. Magnetic mapping of a weathered dike’s cross-section from an exploration trench by in-situ susceptometry permits to analyze past soil deformation in great detail. Weathering and solifluction transforms the simple “vertical sheet” anomalies of dikes into complex, but still interpretable composite patterns, providing a new and promising exploratory approach for field studies concerned with soil creep and pedoturbation.

Assessment of Magnetic Susceptibility of Some Selected Rock Samples from Karu Area, Northcentral Nigeria

Magnetic susceptibility is a very sensitive indicator of magnetic minerals present in rock because any slight variation in magnetic mineralogy is usually reflected by a profound change of susceptibility. However, the knowledge of its mineral composition does not provide adequate information about the rock and mineral composition of rock and properties such as magnetic susceptibility determines the property of rock. Six samples of the rocks were obtained at different two quarries site each located at Nyanya and Karu for the assessment of magnetic susceptibility which were measured with an instrument called magnetic susceptibility meter EM2S+. The results obtained shows that limestone has low magnetic susceptibility compared to other rock samples such as pegmatite, quartzite, gneiss, granite, granite gneiss, sand stone in both site and pegmatite has the low magnetic susceptibility compared to other rock samples in Karu. The average magnetic susceptibility of the rock samples from Nyanya and Karu are 4.11 x 10-4 (SI) and 4.99 x 10-4(SI) respectively. In conclusion, the selected rock samples show that granite gneiss > laterite > sand stone > granite > gneiss > quartzite > pegmatite > limestone. Which indicate that limestone has the low magnetic susceptibility than other rock samples, show the present of Felsic materials while granite gneiss has a very high magnetic susceptibility, as a result of the present of large amount of iron and magnesium in it.

MAGNETIC NANOPARTICLES: THE COBALT

The development of nanoparticles has been intensively pursued because of their technological importance. The magnetic nanoparticulate materials exhibit a series of interesting properties between which are mentioned the electrical, optical, magnetic and chemical properties. Magnetic nanostructures can be used in microelectronic and in medicine as in: magnetic memory storage, magnetic transport of biochemical complexes, magnetic resonance imaging, among others. The magnetic properties of nanoparticles there are very sensitive to its size and form. In this direction, many efforts they have been carried through with the intention of to control the form and distribution of the size of the nanoparticles. In the last few decades nanoparticles constituted by iron oxides had been studied. However, more recently, the focus of the researches has come back to others transitions metals. Amongst these, the cobalt comes being investigated due to its high magnetic susceptibility. In this context, the present article has the aim of to presents and to effect a comparative analysis of the more significant synthetic ways utilized in the present moment to obtain cobalt nanoparticles.

Reconstruction and appraisal of Akunu–Akoko area iron ore deposits using geological and magnetic approaches

Geological mapping and magnetic methods were applied for the exploration of iron ore deposits in the Akunu–Akoko area of Southwestern Nigeria for the purpose of evaluating their geological characteristics and resource potentials. A proton magnetometer measures the vertical, horizontal and total magnetic intensities in gammas. The subsurface geology was interpreted qualitatively and quantitatively. The downward continuations and second vertical derivatives, the small-sized mineralised bodies and shallow features in the study area were mapped. The faults are trending in the following directions: NE–SW, NW–SE, N–S and E–W groups, while the iron ore mineralisation is structurally controlled by two major groups of fault trends, namely, the NE–SW and NW–SE; the N–S and E–W groups are mere occurrences that do not contribute to the structural control of the iron ore mineralisation in Akunu.The upward continuation has a linear feature similar to the principal orientation of the regional faults, while Locations 2 and 3 have relatively high magnetic susceptibility zones; suspected to be iron ore deposits. The depths to the magnetic sources ranged from 25 m to about 250 m.