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Chinese Physics B 2017年第7期26卷 377-382页

作者： m A Ali m m Uddin m n i khan F U Z Chowdhury S m Hoque S i Liba Department of Physics Chittagong University of Engineering and Technology (CUET) materials Science Division Atomic Energy Center

A series of ni0.6-x/2Zn0.4-x/2SnxFe2O4(x = 0.0, 0.05, 0.1, 0.15, 0.2, and 0.3)(nZSFO) ferrite composities have been synthesized from nano powders using a standard solid state reaction technique. The spinel cubic structure of the investigated samples has been confirmed by x-ray diffraction(XRD). The magnetic properties such as saturation magnetization(ms),remanent magnetization(mr), coercive field(Hc), and Bohr magneton(μ) are calculated from the hysteresis loops. The value of msis found to decrease with increasing Sn content in the samples. This change is successfully explained by the variation of A-B interaction strength due to Sn substitution in different sites. The compositional stability and quality of the prepared ferrite composites have also been endorsed by the fairly constant initial permeability(μ’) over a wide range of frequency. The decreasing trend of μ’ with increasing Sn content has been observed. Curie temperature TChas been found to increase with the increase in Sn content. A wide spread frequency utility zone indicates that the nZSFO can be considered as a good candidate for use in broadband pulse transformers and wide band read-write heads for video recording. The composition of x = 0.05 shows unusual results and the possible reason is also mentioned with the established formalism.

关键词： magnetic properties saturation magnetization permeability Curie temperature

Enhancement of coercivity,permeability,and dielectric properties of Co_(0.2)Zn_(0.3)ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for memory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： i.Sardar m.D.Hossain m.S.Sikder m.n.i.khan m.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Department of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Department ofComputer Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh material Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in me mory and high frequency *** the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important *** article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTiR),field emission scanning electron microscopy(FESEm),energy dispersive X-ray(EDX),vibrating sample magnetometer(VSm),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the *** XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu *** FTiR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FESEm images,and it is increased from 121 to 198 *** analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the *** permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric *** dependent resistivity and impedance analysis also show the improved *** the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Permeability EDX Resistivity

influence of Li_(2)CO_(3)addition on electrical and magnetic properties of ni_(0.6)mg_(0.4)Fe_(2)O_(4)

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Journal of Advanced Dielectrics 2020年第3期10卷 43-50页

作者： m.R.Hassan m.T.islam m.n.i.khan Physics Discipline Khulna University Khulna 9208Bangladesh materials Science Division Atomic Energy Centre DhakaBangladesh

in this research,influence of adding Li_(2)CO_(3)(at 0%,2%,4%,6%)on electrical and magnetic properties of ni_(0.6)mg_(0.4)Fe_(2)O_(4)(with 60%ni and 40%mg)ferrite has been *** samples are prepared by solid state reaction method and sintered at 1300℃ for 6 h.X-ray diffraction(XRD)patterns show the samples belong to single-phase cubic structure without any impurity *** magnetic properties(saturation magnetization and coercivity)of the samples have been investigated by VSm and found that the higher concentration of Li_(2)CO_(3)reduces the hysteresis *** resistivity increases with Li_(2)CO_(3)contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are *** dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime,which are due to the presence of resonance between applied frequency and hopping frequency of charge ***,the loss peaks are shifted to the lower frequency with Li_(2)CO_(3)additions.

关键词： Single phase resistivity dielectric constant saturation magnetization coercivity

Optical and electrical properties of crystalline indium tin oxide thin film deposited by vacuum evaporation technique

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Optoelectronics Letters 2019年第5期15卷 356-359页

作者： md.mottaleb Hosen A.K.m.Atique Ullah md.mahbubul Haque S.m.Abdur Rahim K.m.Abdus Sobahan m.n.i.khan Department of Electrical and Electronic Engineering Islamic University Kushtia 7003 Bangladesh nanoscience and Technology Research Laboratory Atomic Energy Centre Bangladesh Atomic Energy Commission Dhaka 1000 Bangladesh Analytical Chemistry Laboratory Chemistry Division Atomic Energy Centre Bangladesh Atomic Energy Commission Dhaka 1000 Bangladesh Department of Physics Jagannath University Dhaka 1100 Bangladesh materials Science Division Atomic Energy Centre Bangladesh Atomic Energy Commission Dhaka 1000 Bangladesh

indium tin oxide(iTO) thin film was deposited on glass substrate by means of vacuum evaporation technique and annealed at 200 ℃, 300℃ and 400 ℃ in air for 1 h. The characterization and properties of the deposited film samples were analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEm), and UV-ViS-niR spectroscopy techniques. From the XRD patterns, it was found that the deposited thin film was of crystalline at an annealing temperature of 400℃. The crystalline phase was indexed as cubic structure with lattice constant and crystallite size of 0.511 nm and 40 nm, respectively. The SEm images showed that the films exhibited uniform surface morphology with well-defined spherical grains. The optical transmittance of iTO thin film annealed at 400 ℃ was improved from 44% to 84% in the wavelength range from 250 nm to 2 100 nm and an optical band gap was measured as 3.86 e V. Hall effect measurement was used to measure the resistivity and conductivity of the prepared film.

关键词： indium tin oxide(iTO) X-ray diffraction(XRD) scanning electron microscopy(SEm)

Correlations of Structural, Dielectric, magnetic and magnetoelectric Properties of Ca1-xSrx(Fe0.5Ta0.5)O3multiferroic Ceramics

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materials Sciences and Applications 2017年第1期8卷 64-84页

作者： m.K.H.Bhuiyan m.A.Gafur m.n.i.khan A.A.momin A.K.m.Akther Hossain Department of Physics Bangladesh University of Engineering&TechnologyDhakaBangladesh Pilot Plant&Process Development Centre DhakaBangladesh materials Science Division Atomic Energy CentreDhakaBangladesh

Conventional solid state reaction technique was used to synthesize Ca1-xSrx(Fe0.5Ta0.5)O3 multiferroic ceramics (where x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5). Powder of ingredients was mixed thoroughly in stoichiometric amount and calcined at 1150°C for 5 h. Disk and toroid shaped samples prepared from each composition were sintered at 1450°C for 5 h. The XRD analysis confirms that all compositions are single phase cubic perovskite structure. The theoretical and bulk density increases with increase of Sr content, which may be attributed to the fact that the atomic weight and density of Sr are larger than those of Ca. The average grain size increased with increasing Sr content up to x = 0.2, and then decreased with further increase of Sr content. Frequency dependent dielectric constant shows usual dielectric dispersion at lower frequencies due to maxwell-Wagner type interfacial polarization. The higher values of real and imaginary part of impedance at lower frequencies are also due to the fact that all kinds of polarization mechanism are present and increase with Sr content indicating the enhancement property of the composition. The continuous dispersion on increasing frequency contributes to the conduction phenomena. Two semicircles correspond to the grain boundary and grain resistance separately. The complex modulus analysis reveals the polaron hopping and negligibly small contribution of electrode effect. The continuous dispersion on increasing frequency may be contributed to the conduction phenomena. The ac conductivity, σac, was derived from the dielectric measurement and it increases with increase of frequency for all the compositions and can also be explained on the basis of polaron hopping mechanism. At higher frequencies conductive grains are more active, and thereby increases of hopping of charge carrier contribute to rise in conductivity. The real part of initial permeability increased with increasing Sr content up to x = 0.2, and then decreased further incr

关键词： Perovskite impedance Spectroscopy initial Permeability Saturation magnetization magnetoelectric Voltage Coefficient

Effect of Cu incorporation on Structure, Densification and magnetic Properties of Polycrystalline Lixni0.2Zn0.8-2xFe2+xO4Ceramics

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Journal of Applied mathematics and Physics 2021年第12期9卷 3211-3229页

作者： Halima Akter Liya Ruhina Akter Abdul Ahad m. n. i. khan m. J. miah Department of Physics Comilla University Cumilla Bangladesh materials Science Division Bangladesh Atomic Energy Commission Dhaka Bangladesh

The polycrystalline Lixni0.2Zn0.8-2xFex+2O4 and Lixni0.1Cu0.1Zn0.8-2xFex+2O4 (x = 0.0, 0.1, 0.2, and 0.3) ferrites were synthesized by the standard solid-state reaction method. The compound was sintered at 1150˚C for ... 详细信息

The polycrystalline Lim>xm>ni0.2Zn0.8-2m>xm>Fem>xm>+2O4 and Lim>xm>ni0.1Cu0.1Zn0.8-2m>xm>Fem>xm>+2O4 (m>xm> = 0.0, 0.1, 0.2, and 0.3) ferrites were synthesized by the standard solid-state reaction method. The compound was sintered at 1150˚C for 5 hours. The effect of Cu substitution and its impact on the crystal structure, microstructure, complex initial permeability and magnetization of the ni-Zn ferrites were studied. The effect of Li+ incorporation on the properties mentioned above was also investigated. X-ray diffraction patterns of the samples indicated a single cubic spinel structure for both the compound. no effect of Cu addition on crystal structure was observed. The density of the ferrites was found to be enhanced because of adding Li whereas the porosity of the samples decreased with the content of Li ions. The average value of grain size increased with the addition of Li content. The samples having Cu ions formed bigger size grains. Frequency-dependent complex initial permeability, loss tangent, and relative quality factor were studied at room temperature using an impedance analyzer in the range of 100 Hz - 120 mHz regions. in the low-frequency region, the prepared samples exhibited a high value of permeability and after a certain frequency, the permeability falls. The value of permeability enhanced with the increase in Li whereas loss tangent was found to be reduced. The relative quality factor graphs described that the compound has excellent frequency stability up to a certain frequency which is suitable to be used in inductors, resistors, capacitors, etc. initial permeability for Lim>xm>ni0.1Cu0.1Zn0.8-2m>xm>Fem>x<

关键词： Ceramics Ferrites Complex initial Permeability Saturation magnetization

Structural and magnetic Properties of Cr3+ Doped mg Ferrites

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World Journal of Condensed matter Physics 2012年第1期2卷 27-35页

作者： Faizun nesa A. K. m. Zakaria m. A. Saeed khan S. m. Yunus A. K. Das S.-G. Eriksson m. n. i. khan m. A. Hakim Bangladesh Atomic Energy Commission Dhaka Bangladesh Chalmers University of Technology Gothenburg Sweden Jahangirnagar Universiry Dhaka Bangladesh

The polycrystalline mgCrxFe2-xO4 ferrites (0.0 ? x ? 1.0) were prepared by conventional solid state ceramic sintering technique in air at 1300?C. X-ray diffraction experiments were carried out on all the samples in order to characterize the materials at room temperature. The X-ray diffraction patterns showed sharp peaks indicating the formation of single phased cubic spinel structure. The lattice parameters of the samples were determined from the X-ray diffraction data using nelson-Riley extrapolation method. it was found that the lattice parameter decreased with increasing Cr concen- tration obeying Vegard’s law. magnetic properties of the samples were measured using an impedance Analyzer. Real and imaginary parts of the complex permeability, loss factor and quality factor were measured as the function of frequency at three different sintering temperatures 1250?C, 1300?C and 1350?C for all the samples in the frequency range 1 kHz to 13 mHz. Frequency stability of the real part of permeability increases with increasing Cr concentration and also with sintering temperature. imaginary part of permeability decreases with increasing frequency and increased with increasing both of the Cr content and sintering temperature. Loss factor decreased with increasing frequency while the quality factor (Q) increased with increasing frequency for all the samples. The temperature de- pendence of initial permeability was measured for all the samples sintered at 1300?C. The Curie temperature (Tc) was determined from the -T curves. The values of Tc were found to be 733 K, 657 K, 583 K, 468 K, 400 K and 317 K for x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, respectively.

关键词： Ferrites Spinel Structure magnetic Properties Permeability Loss Factor Curie Temperature

Arctic sea-ice extent: no record minimum in 2023 or recent years

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Atmospheric and Oceanic Science Letters 2025年第1期18卷 52-55页

作者： Ola m.Johannessen Tor i.Olaussen nansen Scientific Society BergenNorway nansen Environmental and Remote Sensing Center BergenNorway

Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(***^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 ***^(2), 0.794 ***^(2) less than the minimum in 2023. However, the ice extent had decreased by 0.432 ***^(2) compared with 2022. nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. in general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the remainder is caused by natural variability.

关键词： Sea ice Arctic minimum ice Climate

neurocircuit regeneration by extracellular matrix reprogramming

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neural Regeneration Research 2025年第8期20卷 2300-2301页

作者： Shengzhang Su ian n.Levasseur Kimberly m.Alonge Department of medicinal Chemistry University of WashingtonSeattleWAUSA Department of Chemistry University of WashingtonSeattleWAUSA Department of medicine University of Washington Medicine Diabetes InstituteSeattleWAUSA

The brain's extracellular matrix(ECm),which is comprised of protein and glycosaminoglycan(GAG)scaffolds,constitutes 20%-40% of the human brain and is considered one of the largest influencers on brain cell functioning(Soles et al.,2023).Synthesized by neural and glial cells,the brain's ECm regulates a myriad of homeostatic cellular processes,including neuronal plasticity and firing(miyata et al.,2012),cation buffering(moraws ki et al.,2015),and glia-neuron interactions(Anderson et al.,2016).Considering the diversity of functions,dynamic remodeling of the brain's ECm indicates that this understudied medium is an active participant in both normal physiology and neurological diseases.

关键词： matrix programming

Variation in Salt Tolerance of Wheat Cultivars:Role of Glycinebetaine and Ethylene

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Pedosphere 2012年第6期22卷 746-754页

作者： m.i.R.khan n.iQBAL A.mASOOD n.A.khan Department of Botany Aligarh Muslim UniversityAligarh 202002(India)

Four wheat （Triticum aestivum L.） cultivars 711, PBW343, 3765 and WH542 were screened for studying variations in glycinebetaine （GB） content and plant dry mass under 100 mmol L-1 naCl stress. A tolerance index was calculated using plant dry mass data to select salt-tolerant and salt-sensitive types and find association between tolerance index and GB content. Tolerance index has been used as a good criterion to select the tolerant types under high salinity stress. Further, physiological differences in salt-tolerant cultivar 711 and salt-sensitive cultivar WH542 were examined. The salt-tolerant cultivar exhibited greater CB content, which was found correlative with ethylene. The cultivar also showed higher nitrogen （n） content and nitrate reductase activity, reduced glutathione and higher redox state resulting in maximal protection of plant dry mass than the salt-sensitive type. Thus, the content of CB may be considered as important physiological criteria for selecting salt-tolerant wheat types.

关键词： glutathione nitrogen assimilation salt stress