Aspects of Structural and Multiferroic Properties of A- (15% Gd) and B-Site (5–15% Cr) Doped Perovskite BiFeO3 Nanoparticles

M. N. Hossain,M. A. Matin,M. A. Islam,M. M. Rhaman,M. A. Hakim,M. F. Islam 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.4

This report focuses on the investigation of multiferroic properties of 15% Gd and (5–15) % Cr co-doped Bismuth Ferrite (BFO) nanoparticles prepared by sol–gel method. The synthesized pure BFO has shown to be R3c rhombohedral crystal structure which partially transforms to Pnma orthorhombic crystal structure with increasing Cr dopant in co-doped samples. The crystallite size was found to vary from 68 to 22 nm depending on doping level. SEM images exhibited uniform nanoparticles and the average size of particles was shown to vary from 263 to 114 nm which is comparatively higher than that obtained from XRD results due to agglomeration eff ects. Ferroelectric tests exhibited a signifi cant reduction in polarization in doped BFO under an applied fi eld of ± 15 kV/cm. In contrast, the magnetic measurement showed a substantial improvement in ferromagnetic properties of the synthesized samples compared to un-doped one. A prominent exchange anisotropy eff ect was also observed in all the samples at room temperature. In addition, co-doped BFO samples demonstrated a signifi cant reduction in band gap energy from 1.88 to 1.68 eV.

Fabrication of Bismuth Vanadate (BiVO4)Nanoparticles by a Facile Route

M. F. Rahman,M. S. Haque,M. Hasan,M. A. Hakim 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.6

Monoclinic bismuth vanadate (m-BiVO4 ) has attracted many researchers as an advanced photocatalyst for hydrogen production via water splitting and degradation of organic contaminants. In this study, pure m-BiVO4 nanoparticles were fabricated by an easy reproducible solid state route at different temperatures (500 °C, 550 °C, 600 °C, 650 °C and 700 °C) for 2 h. The synthesized materials were characterized by X-ray Diff ractometer where all the diff raction patterns reveal characteristic peaks corresponding to m-BiVO 4 with space group C2/c. Obtained m-BiVO4 particles have the lattice parameters: a = 7.2477 Å, b = 11.6970 Å, c = 5.0900 Å and the volume of the unit cell is 309.23 (106 pm 3 ). Fourier Transform Infrared spectroscopy exhibits formation of Bi–O bond in the prepared nano powders. Ultraviolet–Visible diff use refl ectance spectroscopy suggests that nanostructured BiVO4 particles possess strong energy absorption properties both in visible and ultraviolet region. The particles show red shift of band gap as the calcination temperature rises and possible reasons have been discussed. Energydispersive X-ray spectroscopy confi rms presence of Bi, V, and O without any contaminant, while particle’s morphology was investigated using Field Emission Scanning Electron Microscope.

Structure-based magnetic, electrical and transport properties of Ni–Zn–Co ferrite by V5+ substitution

Hossain M.D.,Khan M.N.I.,Hossain Md Sarowar,Ahned S.J.,Alam M.K.,Liba S.I.,Hakim M.A.,Jamil A.T.M.K. 한국물리학회 2022 Current Applied Physics Vol.43 No.-

This article presents the modification of structure-based magnetic, electronic and transport properties along with the conduction mechanism and its relaxation process in a Ni–Zn–Co ferrite tailored by V5+ substitution at B-site replacing Fe3+ ions. The composition Ni0.7Zn0.2Co0.1Fe2-xVxO4 (0≤ x≤ 0.12) was synthesized by standard solid-state reaction method and all samples were crystallized with a single-phase cubic spinel structure belonging to the Fd3m space group. The lattice constants decreased gradually from 8.3673≽A to 8.3602≽A and the average grain sizes (DSEM) are also decreased from 6.92 μm to 1.99 μm due to V5+ ions substitution at Fe3+ of B-site. However, more than 25% of Fe3+ ions migrate to A-site from B-site due to V5+ substitution at Fe3+ of B-site. In all samples θD does not strictly follow the Anderson’s prediction, rather it monotonically decreases to a low value until x = 0.12. Magnetic phase transition temperature shifted to the lower temperature and the net magnetization (ηeB) decreases due to V5+ substitution in Ni–Zn–Co ferrite. Apart this, during conduction charge carriers should require more energy to jump from one cationic site to other for V5+ substitution in the Ni–Zn–Co ferrite and the activation energy (Ea) is much more higher in V5+ substituted sample. Moreover, long-range interaction with localized relaxation mechanism is observed in V5+ doped samples. The resistance at the grain (Rg) is maximum (243.09 Ω) for the sample x = 0.10 while grain boundary resistance (Rgb) is maximum (5.98×105 Ω) for the sample x = 0.07. However, the higher value of ρdC for x = 0.12 sample ensures to be suitable for electromagnets, transformers, electronic inductors, and at high-frequency applications. Moreover, x = 0.07 sample displays high value of TCR ( -8.6%/K at 418 K) which may be utilized as an infrared detector for night vision bolometer material.

Dilution of the Magnetic Moment of Fe by Cr for Fe73.5-xCrxCu1Nb3Si13.5B9 and the Field-Cooled and Zero-Field-Cooled Behavior for Higher Cr Content

S. S. Sikder,M. A. Hakim,S. Manjura Hoque,Md. Sultan Mahmud,P. Nordblad 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

The temperature and the field dependences of the magnetization have been measured for Fe73:5-xCrxCu1Nb3Si13:5B9 (0 ≤ x ≤ 17.5) prepared by using a melt spin technique. The temperature dependence of the magnetization in the range of 5 to 300 K with an applied field of 1 Tesla for all the compositions follows the relaxation M(T) = M0(1-BT3/2 -CT5/2), which is indicative of the presence of a spin wave excitation. The saturation magnetizations at 5 and 300 K decrease linearly with Cr concentration for the entire composition range, which indicates that a simple dilution of the Fe moment takes place due to Cr substitution. The field-cooled (FC) and the zero-field-cooled (ZFC)magnetizations measured with an applied field of 1 Oe show divergences for x = 10, 12.5, 15 and 17.5, which may be attributed to the magnetic hardening at low temperatures.

Diels-Alder Type Adducts from Hairy Root Cultures of Morus macroura

Nizar Happyana,Euis H. Hakim,Yana M. Syah,Oliver Kayser,Lia D. Juliawaty,Didin Mujahidin,Tri M. Ermayanti,Sjamsul A. Achmad 한국생약학회 2019 Natural Product Sciences Vol.25 No.3

Three Diels-Alder type adducts, guangsangon E (1), chalcomoracin (2) and sorocein I (3) were isolated from hairy root cultures of Morus macroura. The structures of the isolated compounds (1 - 3) were determined by spectroscopic method (NMR and MS), and spectral comparison to literature. Cytotoxic activities of the isolated compounds (1 - 3) were investigated against P-388 murine leukemia cell line. Guangsangon E (1) showed the most potent cytotoxicity against P-388 murine leukemia cell line with IC50 value of 2.75 ± 0.32 µg/mL. To the best of our knowledge, guangsangon E (1) and sorocein I (3) were reported for the first time from the tissue cultures of M. macroura.

Effect of Preparation Routes on the Crystal Purity and Properties of BiFeO3 Nanoparticles

M. A. Matin,M. M. Rhaman,M. N. Hossain,F. A. Mozahid,M. A. Hakim,M. H. Rizvi,M. F. Islam 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.6

Sol–gel as a chemical solution deposition technique is compatible with functional device fabrication technology. Single-phase bismuth ferrite (BiFeO3) mutiferroic with its multi-functionality has extensively been studied for a variety of prospective novel device applications. However, the synthesis of BiFeO3 is confronted with a challenge to produce pure state without any secondary phase. Scarcity of unified process parameters impede justifi cation of best synthesis techniques. In this work, sol–gel methods with and without auto-combustion reactions were used to synthesize bismuth ferrite (BiFeO3) nanoparticles. Different techniques UV–Vis–NIR spectroscopy, XRD, EDS, and SEM were used to investigate the effect of preparation routes on the crystal purity and properties of prepared samples. Synthesized nanoparticles were calcined at temperature between 400 and 800 ◦ C and an optimal calcination temperature was found to be 600 ◦ C. Band-gap was determined by UV–Vis–NIR spectroscopy and found to vary from 1.93 to 2.07 eV. X-ray diff raction (XRD) has confi rmed single phase rhombohedral crystal structure with R3c symmetry. Avg crystallite size was found to be higher (40–68 nm) in auto-combustion reaction compared to that of 23–42 nm obtained in sol–gel method without auto-combustion reaction. The band-gap energy was found to reduce with decreasing crystallite size (above the critical size of 10 nm) following Brus’s eff ective mass model. Induced strain was found to exhibit an inverse relation with crystallite size and displayed substantial reduction in auto-combustion reaction route. The microstructural features were investigated by fi eld emission scanning electronic microscopy and avgparticle size was shown to vary from 107 to 197 nm depending on adopted synthesis route. A low reaction temperature (70 ◦ C–80 ◦ C) without auto-combustion and calcination temperature at 600◦ C were found to be optimal conditions for the preparation of low impurity un-doped bismuth ferrite nanaoparticles.

Optical and Ferroelectric Properties of Bi0.95Gd0.05Fe1−xCrxO3

M. A. Matin,M. N. Hossain,M. M. Islam,M. A. Hakim,M. F. Islam 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.3

In this paper, optical and ferroelectric properties were investigated for gadolinium, Gd3+ (5 at.%) and chromium, Cr3+ (0–8at.%) co-doped of BiFeO3 . Chemical solution deposition (CSD) method was employed as compatible device fabrication technology to synthesize Gd and Cr co-doped multiferroic BiFeO3 (Bi0.95Gd0.05Fe1−xCrxO3 with x = 0–0.08). X-ray diffraction (XRD) analysis confirmed a well-defined crystalline phase with a tendency towards structural change from rhombohedral to orthorhombic symmetry. Crystallite size was found to reduce substantially from 34 to 13.5 nm with increasing the doping concentration of Cr3+ . The field emission scanning electron microscopy (FESEM) demonstrated a significant reduction in grain size of doped BiFeO3 compared to un-doped one following the trend obtained from XRD results. Ferroelectric nature of samples was obtained from polarization versus electric field measurements. Improved ferroelectric order was displayed in co-doped BiFeO3 with a maximum remnant polarization of 0.23 μ C∕cm2 . Diffuse reflectance measurement by UV–Vis–NIR spectroscopy of Gd 3+ and Cr3+ co-doped BiFeO3 has shown a significant reduction in the optical band-gap energy (Eg) to 1.71 eV compared to 2.03 eV of pure BiFeO 3 counterpart.

Effect of Al-doping on optical and electrical properties of spray pyrolytic nano-crystalline CdO thin films

M.K.R. Khan,M. Azizar Rahman,M. Shahjahan,M. Mozibur Rahman,M.A. Hakim,Dilip Kumar Saha,Jasim Uddin Khan 한국물리학회 2010 Current Applied Physics Vol.10 No.3

CdO and Al-doped CdO nano-crystalline thin films have been prepared on glass at 300 ℃ substrate temperature by spray pyrolysis. The films are highly crystalline with grain size (18–32 nm) and found to be cubic structure with lattice constant averaged to 0.46877 nm. Al-doping increased the optical transmission of the film substantially. Direct band gap energy of CdO is 2.49 eV which decreased with increasing Al-doping. The refractive index and dielectric constant varies with photon energy and concentration of Al as well. The conductivity of un-doped CdO film shows metallic behavior at lower temperature region. This behavior dies out completely with doping of Al and exhibits semiconducting behavior for whole measured temperature range. Un-doped and Al-doped CdO is an n-type semiconductor having carrier concentration is of the order of ~1021 cm-3, confirmed by Hall voltage and thermo-power measurements.

해외정보 : 인도의 UNANI 의학 ① - 그 배경과 전망 -

(Hakim M . A . Razzack),신민규 (역) 대구한의대학교 제한동의학술원 1978 황제의학 Vol.3 No.3

해외정보 : 인도의 UNANI 의학 ( 완 ) - 그 배경과 전망 -

(Hakim M . A . Razzack),신민규 (역) 대구한의대학교 제한동의학술원 1978 황제의학 Vol.3 No.4