scholarly journals Room Temperature Magnetic Memory Effect in Cluster-Glassy Fe-Doped NiO Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1318 ◽  
Author(s):  
Ashish Chhaganlal Gandhi ◽  
Tai-Yue Li ◽  
B. Vijaya Kumar ◽  
P. Muralidhar Reddy ◽  
Jen-Chih Peng ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Oxide System ◽  
Precipitation Method ◽  
Magnetic Memory ◽  
Nio Nanoparticles ◽  
Magnetic Anisotropy Energy ◽  
Spintronic Devices ◽  
Co Precipitation

The Fe-doped NiO nanoparticles that were synthesized using a co-precipitation method are characterized by enhanced room-temperature ferromagnetic property evident from magnetic measurements. Neutron powder diffraction experiments suggested an increment of the magnetic moment of 3d ions in the nanoparticles as a function of Fe-concentration. The temperature, time, and field-dependent magnetization measurements show that the effect of Fe-doping in NiO has enhanced the intraparticle interactions due to formed defect clusters. The intraparticle interactions are proposed to bring additional magnetic anisotropy energy barriers that affect the overall magnetic moment relaxation process and emerging as room temperature magnetic memory. The outcome of this study is attractive for the future development of the room temperature ferromagnetic oxide system to facilitate the integration of spintronic devices and understanding of their fundamental physics.

scholarly journals ON SPIN HAMILTONIAN FITS TO MÖSSBAUER SPECTRA OF NiFe2O4 NANOPARTICLES SYNTHESIZED BY CO-PRECIPITATION

2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Jose Higino Dias Filho ◽  
Jorge Luis López Aguilar ◽  
Adriana Silva De Albuquerque ◽  
Renato Dourado Maia ◽  
Wesley De Oliveira Barbosa ◽  
...  
Keyword(s):  
Mössbauer Spectra ◽  
Magnetic Measurements ◽  
Magnetic Transition ◽  
Particle Diameter ◽  
Evolutionary Strategies ◽  
Precipitation Method ◽  
Magnetic Anisotropy Energy ◽  
Magnetic Transition Temperature ◽  
Mossbauer Spectra ◽  
Co Precipitation

Nanocrystalline NiFe2O4 particles prepared by chemical co-precipitation method were studied using magnetic measurements, 57Fe Mössbauer spectroscopy, X-ray diffraction, and transmission electron microscopy. Fits to Mössbauer spectra, in the range of 4.2 K – 300 K, were done using spin hamiltonians to describe both the electronic and nuclear interactions, a model of superparamagnetic relaxation of two levels (spin ½) and stochastic theory, a log-normal particle size distribution function as well as a dependency of the magnetic transition temperature and the anisotropy constant on particle diameter. We have used evolutionary strategies to fit the more complex Mössbauer spectra line shapes. The nanoparticles have an average size of 7 nm and exhibit superparamagnetism at room temperature. The saturation magnetization (Ms) at 4.2 K was determined from M vs. 1/H plots by extrapolating the value of magnetizations to infinite fields, to 24.21 emu/g and coercivity to 3.15 kOe. A magnetic anisotropy energy constant (K) 1.9´105 J/m3, at 4.2 K, were calculated from magnetization measurements. The synthesis, characterization, and functionalization of magnetic nanoparticles is a highly active area of current research located at the interface between materials science, biotechnology, and medicine. Superparamagnetic iron oxides nanoparticles have unique physical properties and have emerged as a new class of diagnostic probes for multimodal tracking and as contrast agents for magnetic resonance imaging (MRI).

Microstructural and Magnetic Studies on Calcined Ni-Zn Ferrite Powders Prepared by Chemical Co-Precipitation Method

2011 ◽  
Vol 264-265 ◽  
pp. 524-529
Author(s):  
I.Z. Rahman ◽  
T.T. Ahmed
Keyword(s):  
Room Temperature ◽  
Magnetic Measurements ◽  
Precipitation Method ◽  
Particle Sizes ◽  
Magnetic Studies ◽  
Zn Ferrite ◽  
Different Temperatures ◽  
Bet Technique ◽  
Co Precipitation ◽  
Cation Distributions

In this paper, we report on structural and magnetic properties of NiZn ferrite powders prepared by chemical co-precipitation method and calcined at different temperatures. Structural, topological and compositional analyses were performed by XRD, SEM, AFM and EDX techniques. The cation distributions in Ni0.8Zn0.2Fe2O4 ferrites were investigated by XPS (Al K radiation: h=1486.6 eV). Particle sizes were measured using AFM techniques and results were compared with BET technique and magnetic measurements were carried out using a vibrating sample magnetometer at room temperature.

Structural and Optical Properties of Pure NiO Nanoparticles and NiO-Mn2O3, NiO-CdO, NiO-Pb2O3, NiO-ZnO Nanocomposites

2021 ◽  
Vol 14 (5) ◽  
pp. 409-417
Keyword(s):  
Nickel Oxide ◽  
Green Emission ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Nio Nanoparticles ◽  
Structural And Optical Properties ◽  
Suitable Material ◽  
Structure Morphology ◽  
Average Grain Size ◽  
Co Precipitation

Abstract: Pure nickel oxide (NiO) nanoparticles and NiO-Mn2O3, NiO-CdO, NiO-Pb2O3, NiO –ZnO nanocomposites were synthesized by co-precipitation method. The PXRD studies revealed that NiO, Mn2O3 and CdO possessed cubic structure, Pb2O3 possessed monoclinic structure, ZnO possessed hexagonal structure and confirmed the presence of polycrystallinity nature of NiO and Mn2O3, CdO, Pb2O3, ZnO in the nanocomposites. The average grain size of NiO nanoparticles was found to be 30.10 nm using Debye Scherer’s formula. The FESEM images of NiO nanoparticles and their nanocomposites revealed spherical shaped structure and NiO-Pb2O3 revealed needle shaped rod-like structure. EDAX analysis confirmed the composition of NiO nanoparticles and their nanocomposites. Raman spectra exhibited characteristic peaks of pure NiO and that of NiO- Mn2O3, NiO-CdO, NiO- Pb2O3, NiO-ZnO in the synthesized nanocomposites. In the PL spectra, blue and green emission was observed in the samples. UV-vis spectra revealed the absorption peaks of NiO nanoparticles and their nanocomposites. Thus, the synthesized NiO- Mn2O3, NiO-CdO, NiO - Pb2O3 and NiO-ZnO nanocomposites can be a suitable material for electrocatalysis applications. Keywords: Nickel oxide nanocomposites, Structure, Morphology, Absorption, Luminescence.

Preparation and Electrochemical Performance of Mn3O4/GR Composites Electrode Material in Supercapacitors

2019 ◽  
Vol 807 ◽  
pp. 50-56
Author(s):  
Yun Long Zhou ◽  
Zhi Biao Hu ◽  
Li Mei Wu ◽  
Jiao Hao Wu
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Precipitation Method ◽  
Electrochemical Performances ◽  
Manganese Sulfate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
A Current ◽  
Discharge Test

Using hydrated manganese sulfate and general type graphene (GR) as raw materials, Mn3O4/GR composite has been successfully prepared by the liquid phase chemical co-precipitation method at room temperature. X-ray diffraction (XRD) was used to investigate the phase structure of Mn3O4powder and Mn3O4/GR composite; The electrochemical performances of the samples were elucidated by cyclic voltammetry and galvanostatic charge-discharge test in 0.5 mol/L Na2SO4electrolyte. The results show that the Mn3O4/GR composite possesses graphene phase and good reversibility; the composite also displays a specific capacitance of 318.8 F/g at a current density of 1 A/g.

Understanding the Magnetic Memory Effect in Fe-Doped NiO Nanoparticles for the Development of Spintronic Devices

2018 ◽  
Vol 2 (1) ◽  
pp. 278-290 ◽  
Author(s):  
Ashish Chhaganlal Gandhi ◽  
R. Pradeep ◽  
Yu-Chen Yeh ◽  
Tai-Yue Li ◽  
Chi-Yuan Wang ◽  
...  
Keyword(s):  
Memory Effect ◽  
Magnetic Memory ◽  
Nio Nanoparticles ◽  
Spintronic Devices

Surface-spin driven room temperature magnetic memory effect in Fe-substituted NiO nanoparticles

2021 ◽  
Vol 536 ◽  
pp. 147856
Author(s):  
Ashish Chhaganlal Gandhi ◽  
Hsin-Hao Chiu ◽  
Kuan-Ting Wu ◽  
Chia-Liang Cheng ◽  
Sheng Yun Wu
Keyword(s):  
Memory Effect ◽  
Room Temperature ◽  
Magnetic Memory ◽  
Nio Nanoparticles ◽  
Surface Spin

Luminescence and absorbance of highly crystalline CaMoO4, SrMoO4, CaWO4 and SrWO4 nanoparticles synthesized by co-precipitation method at room temperature

2010 ◽  
Vol 506 (1) ◽  
pp. 475-481 ◽  
Author(s):  
Titipun Thongtem ◽  
Sukjit Kungwankunakorn ◽  
Budsabong Kuntalue ◽  
Anukorn Phuruangrat ◽  
Somchai Thongtem
Keyword(s):  
Room Temperature ◽  
Precipitation Method ◽  
Co Precipitation

The Mixed Magnetic Property of Co0.76Cu0.74[Fe(CN)6]·7.5H2O

2018 ◽  
Vol 71 (11) ◽  
pp. 914
Author(s):  
Yanfang Xia ◽  
Min Liu ◽  
Duxin Li
Keyword(s):  
Magnetic Field ◽  
Magnetic Moment ◽  
Effective Magnetic Moment ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Co Precipitation ◽  
The Magnetic Field

Co0.76Cu0.74[Fe(CN)6]·7.5H2O was prepared as a powder by a chemical co-precipitation method. The powder X-ray diffraction patterns were indexed to the typical face-centred cubic structure with the lattice parameter a 10.55(2) Å. The temperature dependence of the χ−1 curve obeys the Curie–Weiss law (χ = C/(T – θ)) in the temperature range of 180–300 K. According to Curie–Weiss law, the calculated θ value is −54.82 K. In the paramagnetic state at 300 K, the effective magnetic moment (μeff = (8χT)1/2) is 3.58 μB per formula unit. The calculated theoretical effective magnetic moment is 4.06 μB. The magnetic field cooling measurements under a 200 Oe applied magnetic field show that the saturation magnetization value at 2 K of the complex Co0.76Cu0.74[Fe(CN)6]·7.5H2O is 1.528 emu g−1.

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