scholarly journals Ferromagnetic behavior of the Zn-Mn-O system

2009 ◽  
Vol 74 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Branka Babic-Stojic ◽  
Dusan Milivojevic ◽  
Jovan Blanusa
Keyword(s):  
Thermal Treatment ◽  
Room Temperature Ferromagnetism ◽  
Ferromagnetic Phase ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Transmission Electron ◽  
Zno Crystal ◽  
Thermally Treated

Polycrystalline Zn-Mn-O samples with nominal manganese concentrations x = 0.01, 0.04 and 0.10 were synthesized by a solid state reaction route using (ZnC2O4?2H2O)1-x and (MnC2O4?2H2O)x. Thermal treatment of the samples was performed in air at temperatures 673, 773, 873, 973 and 1173 K for x = 0.01 and at the temperature 773 K for x = 0.04 and 0.10. The samples were investigated by X-ray diffraction, thermogravimetry, differential thermal analysis, transmission electron microscopy, magnetization measurements and electron paramagnetic resonance. X-Ray diffraction was also performed on MnO2 thermally treated at temperatures 673, 773, 873, 973, 1073 and 1173 K. Room temperature ferromagnetism was observed in the Zn-Mn-O samples with x = 0.01 thermally treated at low temperatures (673 and 773 K) and in the sample with x = 0.04 thermally treated at 773 K. It seems that the ferromagnetic phase could originate from interactions between Mn2+ and acceptor defects incorporated in the ZnO crystal lattice during the thermal treatment of the samples.

Structural and Magnetic Properties of the Zn-Mn-O System

2007 ◽  
Vol 555 ◽  
pp. 95-100
Author(s):  
D. Milivojević ◽  
Jovan Blanuša ◽  
V. Spasojević ◽  
V. Kusigerski ◽  
B. Babić-Stojić
Keyword(s):  
Room Temperature Ferromagnetism ◽  
Manganese Concentration ◽  
Ferromagnetic Phase ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Mn Oxide ◽  
Different Temperatures ◽  
Electron Paramagnetic

Zn-Mn-O semiconductor crystallites with nominal manganese concentration x = 0.01, 0.02, 0.04 and 0.10 were synthesized by a solid state reaction route using oxalate precursors. Thermal treatment procedure was carried out in air at different temperatures in the range 400 - 900°C. The samples were investigated by X-ray diffraction, magnetization measurements and electron paramagnetic resonance. X-ray analysis reveals that dominant crystal phase in the Zn-Mn-O system corresponds to the wurtzite structure of ZnO. Room temperature ferromagnetism is observed in the Zn-Mn-O samples with lower manganese concentration, x ≤ 0.04, thermally treated at low temperature (500°C). Saturation magnetization in the sample with x = 0.01 is found to be 0.05 μB/Mn. The ferromagnetic phase seems to be developed by Zn diffusion into Mn-oxide grains.

STRUCTURAL AND MAGNETIC PROPERTIES OF NANOCRYSTALLINE Sn0.98Co0.02O2 UNDER DIFFERENT ANNEALING CONDITIONS

2011 ◽  
Vol 10 (01n02) ◽  
pp. 313-317
Author(s):  
SUNITA MOHANTY ◽  
S. RAVI ◽  
H. S. JENA ◽  
V. MANIVANNAN
Keyword(s):  
Single Phase ◽  
Room Temperature Ferromagnetism ◽  
Magnetization Measurement ◽  
Ferromagnetic Behavior ◽  
Magnetic Polaron ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
X Ray ◽  
Annealing Conditions ◽  
Transmission Electron

Nanocrystalline samples of pure and 2 at% Co -doped SnO 2 was prepared by a co-precipitate technique with a crystallite size of the order 10 nm. The homogeneity and single-phase nature of the sample was confirmed by using various characterization techniques, such as X-ray diffraction, transmission electron microscope, and Fourier infrared spectroscopy. Magnetization measurement shows a signature of room temperature ferromagnetism. The reduction in magnetization with decrease in crystalline size has been explained as a result of restriction in the range of bound magnetic polaron interaction. The samples prepared under nitrogen gas environment exhibit improvement in ferromagnetic behavior and enhanced electrical conductivity.

Fabrication, characterization and magnetic properties of Na-doped ZnO nanorods

2016 ◽  
Vol 09 (03) ◽  
pp. 1650039 ◽  
Author(s):  
Jingyuan Piao ◽  
Li-Ting Tseng ◽  
Kiyonori Suzuki ◽  
Jiabao Yi
Keyword(s):  
Magnetic Measurements ◽  
Zno Nanorods ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Shallow Donors ◽  
Na Doping ◽  
Transmission Electron ◽  
Doped Zno ◽  
Electron Paramagnetic

Na-doped ZnO nanorods have been fabricated through a hydrothermal method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses indicate that the d spacing of ZnO increases with increasing doping concentration, suggesting the effective incorporation of dopant Na in the samples. Electron paramagnetic resonance (EPR) measurements indicate that there are shallow donors in pure ZnO samples and the shallow donors are strongly prohibited by Na doping. In addition, the resonance at g = 2.005 suggests the formation of Zn vacancies. Magnetic measurements indicate that pure ZnO is paramagnetic and Na doping leads to ferromagnetism at room temperature. Moreover, 0.5% Na-doped ZnO nanorods exhibits the largest saturation magnetization.

Hydrothermal Synthesis and Room Temperature Ferromagnetism of Ni-Doped Rod-Like ZnO Particles

2014 ◽  
Vol 934 ◽  
pp. 71-74
Author(s):  
Lian Mao Hang ◽  
Zhao Ji Zhang ◽  
Zhi Yong Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Hexagonal Wurtzite Structure ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Particles

Ni-doped rod-like ZnO particles with doping concentration of 1 at.% were synthesized at 200°C by hydrothermal method and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and superconducting quantum interference device (SQUID). The results show that the as-synthesized samples are pure hexagonal wurtzite structure without metallic Ni or other secondary phases and display rod-like shape with smooth surface. The magnetization measurements reveal that the Ni-doped rod-like ZnO particles show ferromagnetic behavior at room temperature. The saturation magnetization and coercive field are 0.0046 emu/g and 15 Oe, respectively.

Above Room-Temperature Ferromagnetism in GaN Powders by Calcinations with CuO

2006 ◽  
Vol 941 ◽  
Author(s):  
Lori Noice ◽  
Bjoern Seipel ◽  
Rolf Erni ◽  
Amita Gupta ◽  
Chunfei Li ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Room Temperature Ferromagnetism ◽  
Scanning Probe ◽  
Electronic Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Oxide Phases ◽  
Probe Transmission ◽  
Electron Energy Loss

ABSTRACTGallium nitride powders were calcined with copper oxide in either air or N2 and analyzed by means of powder X-ray diffraction (XRD), high-resolution parallel illumination (HRTEM) and scanning probe transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDXS), and electron energy loss spectroscopy (EELS) in order to address the structural and electronic effects of Cu-incorporation into GaN. Gallium oxide and multiple copper oxide phases corresponding to the calcination environment were detected. Significant changes in the lattice parameters and electronic structure of the N2-processed GaN indicate incorporation of both copper and oxygen into the GaN lattice as well as changes in the chemical bonding due to the calcinations process. SQUID magnetometer measurements at 300 K demonstrated ferromagnetism in selected samples.

scholarly journals Zn-Mn-O: Ferromagnet at room temperature

2007 ◽  
Vol 61 (3) ◽  
pp. 147-151
Author(s):  
Dusan Milivojevic ◽  
Jovan Blanusa ◽  
Vojislav Spasojevic ◽  
Vladan Kusigerski ◽  
Branka Babic-Stojic
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Diffraction Method ◽  
Solid State Reaction Method ◽  
Paramagnetic Resonance ◽  
Reaction Method ◽  
X Ray ◽  
Electron Paramagnetic ◽  
Mn Oxides ◽  
Thermally Treated

Semiconductor Zn-Mn-O crystallites were synthesized by a solid state reaction method starting from the thermal decomposition of the appropriate oxalates. Samples were thermally treated in air at temperatures ranging from 400 to 900?C. The nominal concentrations of manganese werex = 0.01, 0.02, 0.04 and 0.10. The samples were investigated by the X-ray powder diffraction method, magnetization measurements and by electron paramagnetic resonance. X-ray diffractgrams show a dominant wurtzite structure of Zn-Mn-O. Room temperature ferromagnetism was observed in Zn-Mn-O samples with manganese concentrations x ? 0.04, thermally treated at low temperature (500?C). The saturation magnetiza?tion for the sample with x = 0.01 was 0.05 ?B/Mn. The room temperature ferromagnetism seems to be due to the diffusion of Zn into the Mn-oxides grains.

The Effect of Thermal Treatment on the Structure of Palygorskite Used for Flue Gas SO2 Removal

2011 ◽  
Vol 356-360 ◽  
pp. 698-703 ◽  
Author(s):  
Xian Long Zhang ◽  
Wei Ping Jiang ◽  
Xue Ping Wu ◽  
Bo Wen Shi ◽  
Bao Jun Yang ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Structural Properties ◽  
Flue Gas ◽  
Temperature Programmed Desorption ◽  
Flue Gas Desulfurization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Sites ◽  
Transmission Electron ◽  
Temperature Programmed

Palygorskite is widely used as industrial adsorbent and also potential for flue gas desulfurization by adsorption of SO2. The effect of thermal treatment on Palygorskite’s structural properties and its performance in SO2adsorption were investigated. The textural and structural properties of the prepared palygorskite adsorbent were characterized by X-ray diffraction, transmission electron microscopy and temperature programmed desorption. The result showed the channel of Palygorskite is partial collapsed and the structure is not changed ultimately when thermally treated below 300 °C. The structure of Palygorskite is Gradually changed when the treating temperature is higher than 300 °C and is damaged entirety till 800 °C. As a result, the adsorption capacity of SO2on Palygorskite decreased drastically. It is suggested that the presences of surface adorbed water and zeolitic water which occupy a large number of adsorption sites are disadvantage for the adsorption of SO2, and dissimilarly the presence of crystal-bonded water is favorable.

scholarly journals Dilute Magnetic SemiconductorCu2FeSnS4Nanocrystals with a Novel Zincblende Structure

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Xiaolu Liang ◽  
Xianhua Wei ◽  
Daocheng Pan
Keyword(s):  
Diluted Magnetic Semiconductor ◽  
Magnetic Semiconductor ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Nir Absorption ◽  
Diluted Magnetic ◽  
Average Size

Diluted magnetic semiconductorCu2FeSnS4nanocrystals with a novel zincblende structure have been successfully synthesized by a hot-injection approach. Cu+, Fe2+, and Sn4+ions occupy the same position in the zincblende unit cell, and their occupancy possibilities are 1/2, 1/4, and 1/4, respectively. The nanocrystals were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive spectroscopy (EDS), and UV-vis-NIR absorption spectroscopy. The nanocrystals have an average size of 7.5 nm and a band gap of 1.1 eV and show a weak ferromagnetic behavior at low temperature.

Synthesis and characterization of 3D Cu0.45Mn0.55O2 nanoflowers with novel photoluminescence and magnetic properties

2014 ◽  
Vol 28 (09) ◽  
pp. 1450071
Author(s):  
Arbab Mohammad Toufiq ◽  
Fengping Wang ◽  
Qurat-ul-ain Javed ◽  
Quanshui Li ◽  
Yan Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Three Dimensional ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Growth Method ◽  
First Time

In this paper, three-dimensional (3D) Cu 0.45 Mn 0.55 O 2 nanoflowers self-assembled by interconnecting dense stacked single-crystalline nanoplates have been prepared using the template-free hydrothermal growth method. The morphology, phase structure and composition of the as-prepared nanomaterial were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDX). FESEM and TEM analyses show that the size of 3D Cu 0.45 Mn 0.55 O 2 nanoflowers is in the range of 1–1.5 μm and the thickness of interconnected nanoplates is about 40 nm on the average. The photoluminescence (PL) spectra of the as-prepared Cu 0.45 Mn 0.55 O 2 nanostructures at room temperature exhibits prominent emission bands located in red–violet spectral region. Moreover, magnetic investigations revealed the weak ferromagnetic behavior of the as-prepared Cu 0.45 Mn 0.55 O 2 nanoflowers and reported for the first time using vibrating sample magnetometer (VSM).

scholarly journals Zn2+ substituted superparamagnetic MgFe2O4 spinel-ferrites: Investigations on structural and spin-interactions

2020 ◽  
Vol 9 (5) ◽  
pp. 576-587
Author(s):  
Lakshita Phor ◽  
Surjeet Chahal ◽  
Vinod Kumar
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spinel Phase ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Spin Interactions ◽  
Transmission Electron ◽  
Maximum Magnetization ◽  
Zn Content

Abstract Nano-magnetic ferrites with composition Mg1−xZnxFe2O4 (x = 0.3, 0.4, 0.5, 0.6, and 0.7) have been prepared by coprecipitation method. X-ray diffraction (XRD) studies showed that the lattice parameter was found to increase from 8.402 to 8.424 Å with Zn2+ ion content from 0.3 to 0.7. Fourier transform infrared (FTIR) spectra revealed two prominent peaks corresponding to tetrahedral and octahedral at around 560 and 430 cm−1 respectively that confirmed the spinel phase of the samples. Transmission electron microscopy (TEM) images showed that the particle size was noted to increase from 18 to 24 nm with an increase in Zn content from x = 0.3 to 0.7. The magnetic properties were studied by vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) which ascertained the superparamagnetic behavior of the samples and contribution of superexchange interactions. The maximum magnetization was found to vary from 23.80 to 32.78 emu/g that increased till x = 0.5 and decreased thereafter. Further, X-ray photoelectron spectroscopy (XPS) was employed to investigate the chemical composition and substantiate their oxidation states.

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