Ag2S–CoS2 hetero-nanostructures: One-pot colloidal synthesis and improved magnetic properties

2014 ◽  
Vol 07 (03) ◽  
pp. 1450024 ◽  
Author(s):  
Yuanjun Liu ◽  
Aihua Yuan ◽  
Guoxing Zhu ◽  
Chunlin Bao ◽  
Rongxian Zhang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Transition Temperature ◽  
Saturation Magnetization ◽  
Magnetic Materials ◽  
Superionic Conductor ◽  
Colloidal Synthesis ◽  
One Pot ◽  
Chemical Route

Ag 2 S – CoS 2 hetero-nanostructures with well defined and sharp hetero-interface were synthesized with a simple one-pot colloidal chemical route. It is proposed that the Ag 2 S nanoparticles with superionic conductor properties play a catalyst role inducing the growth of CoS 2. The magnetic properties of the Ag 2 S – CoS 2 hetero-nanostructures were investigated, which gives a saturation magnetization of 8.3 emu/g at 1.8 K and transition temperature of 120 K. It is believed that the reported results would give some hints to the development of multifunction magnetic materials.

Preparation and Magnetic Properties of La Substituted Barium Ferrites Synthesized by the Oxide one Pot Synthesis (OOPS) Process

2013 ◽  
Vol 634-638 ◽  
pp. 2250-2253 ◽  
Author(s):  
Sitthisak Sorlateap ◽  
Wirunya Keawwattana
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Crystalline Structure ◽  
Coercive Field ◽  
Barium Ferrite ◽  
One Pot ◽  
Xrd Pattern ◽  
One Pot Synthesis ◽  
Ferrite Structure ◽  
Barium Ferrites

Lanthanum (La) substituted barium ferrite, Ba1-xLaxFe12O19(x=0.00-0.40) has been synthesized by the oxide one pot synthesis (OOPS) process. The crystalline structure and magnetic properties have been investigated by means of XRD, SEM and VSM. The XRD pattern matched with the barium ferrite structure. The saturation magnetization (Ms) and coercive field (Hc) of ferrites increased by substitution of La ions on Ba sites at the content up to x=0.15 and then decrease.

scholarly journals Exchange-Coupling Behavior in SrFe12O19/La0.7Sr0.3MnO3 Nanocomposites

Ceramics ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 100-111 ◽  
Author(s):  
Jiba Nath Dahal ◽  
Dipesh Neupane ◽  
Sanjay R. Mishra
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Exchange Coupling ◽  
Synthesis Method ◽  
Temperature Hysteresis ◽  
One Pot ◽  
Simple Method ◽  
Soft Phase ◽  
Squareness Ratio ◽  
Auto Combustion

Magnetically hard-soft (100-x) SrFe12O19–x wt % La0.7Sr0.3MnO3 nanocomposites were synthesized via a one-pot auto-combustion technique using nitrate salts followed by heat treatment in air at 950 °C. X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM) were used to characterize the structural and magnetic properties of the samples. XRD spectra revealed the formation of a mixture of ferrite and magnetite phases without any trace of secondary phases in the composite. Microstructural images show the proximity grain growth of both phases. The room temperature hysteresis loops of the samples showed the presence of exchange-coupling between the hard and soft phases of the composite. Although saturation magnetization reduced by 41%, the squareness ratio and coercivity of the nanocomposite improved significantly up to 6.6% and 81.7%, respectively, at x = 40 wt % soft phase content in the nanocomposite. The enhancement in squareness ratio and coercivity could be attributed to the effective exchange-coupling interaction, while the reduction in saturation magnetization could be explained on the basis of atomic intermixing between phases in the system. Overall, these composite particles exhibited magnetically single-phase behavior. The adopted synthesis method is low cost and rapid and results in pure crystalline nanocomposite powder. This simple method is a promising way to tailor and enhance the magnetic properties of oxide-based hard-soft magnetic nanocomposites.

X-Ray Investigations and Magnetic Properties of CuCr2-xSnxSe4 - Compounds

2010 ◽  
Vol 163 ◽  
pp. 208-212 ◽  
Author(s):  
Izabela Jendrzejewska ◽  
Paweł Zajdel ◽  
Jerzy Mroziński ◽  
Ewa Maciążek ◽  
Tomasz Goryczka ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Transition Temperature ◽  
Spin Glass ◽  
Saturation Magnetization ◽  
Magnetic Structure ◽  
Spinel Structure ◽  
X Ray ◽  
Sn Doping ◽  
Jahn Teller ◽  
Local Distortions

We have observed that doping CuCr2Se4 with tin introduces and then increases the tetrahedral deformation of the spinel structure, which can be connected with the Jahn-Teller (JT) distortion due to Cr2+ ions in antiprismatic environment. The presence of Cr2+ is corroborated by the increase of the saturation magnetization above the 6μB value expected for the 2 Cr3+ ions. In the high limit of the high Sn doping the deformation is decreased, which we attribute to elimination of the JT condition by the increased local distortions. With the tin doping the magnetic structure evolves from the ferromagnet, through spin-glass like to the antiferromagnetic due to increased AF coupling in the system. This is corroborated by the decreasing transition temperature and the Curie-Weiss parameter.

Structural, Morphological and Magnetic Characterization of Sm-substituted Ni-Zn Ferrite

2020 ◽  
Vol 10 (2) ◽  
pp. 152-156 ◽  
Author(s):  
Muhammad Hanif bin Zahari ◽  
Beh Hoe Guan ◽  
Lee Kean Chuan ◽  
Afiq Azri bin Zainudin
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Saturation Magnetization ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Rare Earth Ions ◽  
Ion Concentration ◽  
Zn Ferrite ◽  
Auto Combustion ◽  
Combustion Technique

Background: Rare earth materials are known for its salient electrical insulation properties with high values of electrical resistivity. It is expected that the substitution of rare earth ions into spinel ferrites could significantly alter its magnetic properties. In this work, the effect of the addition of Samarium ions on the structural, morphological and magnetic properties of Ni0.5Zn0.5SmxFe2-xO4 (x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) synthesized using sol-gel auto combustion technique was investigated. Methods: A series of Samarium-substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5SmxFe2-xO4 where x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by sol-gel auto-combustion technique. Structural, morphological and magnetic properties of the samples were examined through X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) and Vibrating Sample Magnetometer (VSM) measurements. Results: XRD patterns revealed single-phased samples with spinel cubic structure up to x= 0.04. The average crystallite size of the samples varied in the range of 41.8 – 85.6 nm. The prepared samples exhibited agglomerated particles with larger grain size observed in Sm-substituted Ni-Zn ferrite as compared to the unsubstituted sample. The prepared samples exhibited typical soft magnetic behavior as evidenced by the small coercivity field. The magnetic saturation, Ms values decreased as the Sm3+ concentration increases. Conclusion: The substituted Ni-Zn ferrites form agglomerated particles inching towards more uniform microstructure with each increase in Sm3+ substitution. The saturation magnetization of substituted samples decreases with the increase of samarium ion concentration. The decrease in saturation magnetization can be explained based on weak super exchange interaction between A and B sites. The difference in magnetic properties between the samples despite the slight difference in Sm3+ concentrations suggests that the properties of the NiZnFe2O4 can be ‘tuned’, depending on the present need, through the substitution of Fe3+ with rare earth ions.

The Structure and Magnetic Properties of NiZn-Ferrite Films Deposited by Magnetron Sputtering at Room Temperature

2013 ◽  
Vol 690-693 ◽  
pp. 1702-1706 ◽  
Author(s):  
Shuang Jun Nie ◽  
Hao Geng ◽  
Jun Bao Wang ◽  
Lai Sen Wang ◽  
Zhen Wei Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetron Sputtering ◽  
Saturation Magnetization ◽  
Room Temperature ◽  
Oxygen Flow ◽  
Flow Ratio ◽  
Study Results ◽  
Ferrite Thin Films ◽  
Ferrite Films

NiZn-ferrite thin films were deposited onto silicon and glass substrates by radio frequency magnetron sputtering at room temperature. The effects of the relative oxygen flow ratio on the structure and magnetic properties of the thin films were investigated. The study results reveal that the films deposited under higher relative oxygen flow ratio show a better crystallinity. Static magnetic measurement results indicated that the saturation magnetization of the films was greatly affected by the crystallinity, grain dimension, and cation distribution in the NiZn-ferrite films. The NiZn-ferrite thin films with a maximum saturation magnetization of 151 emucm-3, which is about 40% of the bulk NiZn ferrite, was obtained under relative oxygen flow ratio of 60%.

scholarly journals Specific Absorption Rate Dependency on the Co2+ Distribution and Magnetic Properties in CoxMn1-xFe2O4 Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1231
Author(s):  
Venkatesha Narayanaswamy ◽  
Imaddin A. Al-Omari ◽  
Aleksandr S. Kamzin ◽  
Bashar Issa ◽  
Huseyin O. Tekin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Field Strength ◽  
Saturation Magnetization ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Ferrite Nanoparticles ◽  
Cofe2o4 Nanoparticles ◽  
Specific Absorption ◽  
Octahedral Sites ◽  
Mixed Ferrite

Mixed ferrite nanoparticles with compositions CoxMn1-xFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) were synthesized by a simple chemical co-precipitation method. The structure and morphology of the nanoparticles were obtained by X-ray diffraction (XRD), transmission electron microscope (TEM), Raman spectroscopy, and Mössbauer spectroscopy. The average crystallite sizes decreased with increasing x, starting with 34.9 ± 0.6 nm for MnFe2O4 (x = 0) and ending with 15.0 ± 0.3 nm for CoFe2O4 (x = 1.0). TEM images show an edge morphology with the majority of the particles having cubic geometry and wide size distributions. The mixed ferrite and CoFe2O4 nanoparticles have an inverse spinel structure indicated by the splitting of A1g peak at around 620 cm−1 in Raman spectra. The intensity ratios of the A1g(1) and A1g(2) peaks indicate significant redistribution of Co2+ and Fe3+ cations among tetrahedral and octahedral sites in the mixed ferrite nanoparticles. Magnetic hysterics loops show that all the particles possess significant remnant magnetization and coercivity at room temperature. The mass-normalized saturation magnetization is highest for the composition with x = 0.8 (67.63 emu/g), while CoFe2O4 has a value of 65.19 emu/g. The nanoparticles were PEG (poly ethylene glycol) coated and examined for the magneto thermic heating ability using alternating magnetic field. Heating profiles with frequencies of 333.45, 349.20, 390.15, 491.10, 634.45, and 765.95 kHz and 200, 250, 300, and 350 G field amplitudes were obtained. The composition with x = 0.2 (Co0.2Mn0.8Fe2O4) with saturation magnetization 57.41 emu/g shows the highest specific absorption rate (SAR) value of 190.61 W/g for 10 mg/mL water dispersions at a frequency of 765.95 kHz and 350 G field strength. The SAR values for the mixed ferrite and CoFe2O4 nanoparticles increase with increasing concentration of particle dispersions, whereas for MnFe2O4, nanoparticles decrease with increasing the concentration of particle dispersions. SARs obtained for Co0.2Mn0.8Fe2O4 and CoFe2O4 nanoparticles fixed in agar ferrogel dispersions at frequency of 765.95 kHz and 350 G field strength are 140.35 and 67.60 W/g, respectively. This study shows the importance of optimizing the occupancy of Co2+ among tetrahedral and octahedral sites of the spinel system, concentration of the magnetic nanoparticle dispersions, and viscosity of the surrounding medium on the magnetic properties and heating efficiencies.

Sign in / Sign up

Export Citation Format

Share Document