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I. Mălăescu, Antoanetta Lungu, C. N. Marin, Paulina Vlăzan and Paula Sfirloagă


Two samples of manganese ferrite powder were obtained by the calcination method (sample A) and hydrothermal method (sample B). The crystal structure of the samples has been determined using X-ray diffraction analysis (XRD). The results shown that the sample A has three phases (FeMnO3, Mn2O3 and Fe2O3) and the prevailing phase is FeMnO3 with perovskite structure and the sample B has only a single phase (MnFe2O4).

The grain morphology was analyzed by scanning electron microscopy (SEM) and the compositional analysis was done by energy dispersive spectroscopy (EDAX).

Measurements of the frequency (f) and temperature (T) dependent complex impedance, Z(f, T) = Z’(f, T) - i Z’’(f, T) of the samples over the frequency range 20 Hz - 2 MHz, at various temperature values from 300C to 1100C are presented. From these measurements, we have shown that the temperature dependence of the relaxation time is of Arhenius type, which suggests that the conduction process is thermally activated. The values obtained for the activation energy Ea, are: 16meV (sample A) and 147.65meV (sample B).

Applying complex impedance spectroscopy technique, the obtained results shows the shape of a single semicircle at each temperature over the measurement range, meaning that the electrical process obeys to a single relaxation mechanism. The impedance and related parameters of the electrical equivalent circuit depend on the temperature and the microstructure of samples. The resistive and capacitive properties of the investigated samples are dominated with the conduction and relaxation processes associated with the grain boundaries mechanism..

Open access

Pegah Moradi Khaniabadi, Daryoush Shahbazi-Gahrouei, Amin Malik Shah Abdul Majid and Bita Moradi Khaniabadi

fine stabilized superparamagnetic nanoparticles of Zn 2+ substituted manganese ferrite. Journal of Magnetism and Magnetic Materials. 2015;393:429-436. [15] Hattrup L, Gendler J. MUC1 alters oncogenic events and transcription in human breast cancer cells. Breast Cancer Research. 2006;8(4):R37. [16] Wang L, Ma J, Liu F, et al. Expression of MUC1 in primary and metastatic human epithelial ovarian cancer and its therapeutic significance. Gynecologic Oncology. 2007;105(3):695-702. [17] Boult K, Borri M, Jury A, et al. Investigating intracranial tumour

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Daryoush Shahbazi-Gahrouei, Pegah Moradi Khaniabadi, Saghar Shahbazi-Gahrouei, Amir Khorasani and Farshid Mahmoudi

. Nanomedicine. 2018; 13(20): 2563-2578. [87] Li J, Wu C, Hou P, et al. One-pot preparation of hydrophilic manganese oxide nanoparticles as T1 nano-contrast agent for molecular magnetic resonance imaging of renal carcinoma in vitro and in vivo. Biosensors and Bioelectronics. 2018;102:1-8. [88] Liu K, Yan X, Xu Y-J, et al. Sequential growth of CaF 2: Yb, Er@ CaF 2: Gd nanoparticles for efficient magnetic resonance angiography and tumor diagnosis. Biomaterials Science. 2017;5(12):2403-2415. [89] Ma L, Liu Y, Liu Liu L, et al. Simultaneous activation of short

Open access

Vanya Koleva, Teodora Koynova, Asya Dragoeva and Nikolay Natchev

.; Zhu, T.; Li, M.; He, J.; Huang, R., Heavy Metal Contamination in Soil and Brown Rice and Human Health Risk Assessment near Three Mining Areas in Central China, Journal of Healthcare Engineering , 2017 , Article ID 4124302. [35]. Dabkowska-Naskret, H.; Jaworska, H., Manganese mobility in soils under the impackt of alkaline dust emission, J Elem , 2013 , 3 :371-379. doi:10.5601/jelem.2013.18.3.02 [36]. O’Neal1, S.; Zheng, W., Manganese Toxicity Upon Overexposure: a Decade in Review, Curr Environ Health Rep