Effect of sintering temperature on the synthesis of LiZnMnFe microwave ceramics with controllable electro/magnetic properties

Author(s):  
K.D. Martinson ◽  
A.A. Ivanov ◽  
I.B. Panteleev ◽  
V.I. Popkov
2009 ◽  
Vol 24 (2) ◽  
pp. 324-332 ◽  
Author(s):  
X.T. Liew ◽  
K.C. Chan ◽  
L.B. Kong

This paper reports on the preparation and characterization of nickel ferrite (NiFe1.98O4) ceramics doped with Bi2O3 as sintering aid. Focus has been on the effects of concentration of Bi2O3 and sintering temperature on the densification, grain growth, dielectric, and magnetic properties of the NiFe1.98O4 ceramics, with an aim at developing magnetodielectric properties, with almost equal real permeability and permittivity, as well as sufficiently low magnetic and dielectric loss tangents, over 3 to 30 MHz (high frequency or HF band). X-ray diffraction results indicated that there is no obvious reaction between NiFe1.98O4 and Bi2O3, at Bi2O3 levels of up to 7 wt% and temperatures up to 1150 °C. The addition of Bi2O3 facilitated a liquid phase sintering mechanism for the densification of NiFe1.98O4 ceramics. The addition of Bi2O3 not only improved the densification but also promoted the grain growth of NiFe1.98O4 ceramics. To achieve sufficiently low dielectric loss tangent, the concentration of Bi2O3 should not be less than 5 wt%. The low dielectric loss tangents of the samples doped with high concentrations of Bi2O3 can be attributed to the full densification of the ceramics. Magnetic properties of the NiFe1.98O4 ceramics, as a function of sintering temperature and Bi2O3 concentration, can be qualitatively explained by the Globus model. Promising magnetodielectric properties have been obtained in the sample doped with 5% Bi2O3 and sintered at 1050 °C for 2 h. The sample has almost equal values of permeability and permittivity of ∼12, together with low dielectric and magnetic loss tangents, over 3 to 30 MHz. This material might be useful for the miniaturization of HF (3 to 30 MHz) antennas.


2007 ◽  
Vol 20 (6) ◽  
pp. 739-742 ◽  
Author(s):  
Yuan-xun Li ◽  
Huai-wu Zhang ◽  
Ying-li Liu ◽  
John Q. Xiao

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2504 ◽  
Author(s):  
Dariusz Bochenek ◽  
Przemysław Niemiec

In this work, PbFe1/2Nb1/2O3 (PFN) ceramic samples synthesized by chemically wet method (precipitation from the solution) were obtained. Due to the tendency to form powder agglomerates, the synthesized powder was subjected to ultrasound. The sintering was carried out under various technological conditions, mainly through controlling the sintering temperature. -X-ray powder-diffraction (XRD), scanning electron microscope (SEM) microstructure analysis, as well as the examinations of dielectric, ferroelectric, and magnetic properties of the PFN ceramics were carried out. Studies have shown that hard ceramic agglomerates can be partially minimized by ultrasound. Due to this treatment, closed porosity decreases, and the ceramic samples have a higher density. Optimization and improvement of the technological process of the PFN material extends the possibility of its use for the preparation of multiferroic composites or multicomponent solid solutions based on PFN. Such materials with functional properties find applications in microelectronic applications, e.g., in systems integrating ferroelectric and magnetic properties in one device. The optimal synthesis conditions of PFN ceramics were determined to be 1050 °C/2 h.


2021 ◽  
Vol 16 (3) ◽  
pp. 517-524
Author(s):  
Poppy Puspitasari ◽  
A. Muhammad ◽  
A. A. Permanasari ◽  
T. Pasang ◽  
S. M. S. N. S. Zahari ◽  
...  

Samarium cobalt is known as super high density magnetic material with large magnetic anisotropy energy. Samarium–cobalt exhibits manipulative magnetic properties as a rare-earth material which has different properties in a low sintering temperature. It is therefore of paramount importance to investigate samarium cobalt (Sm2Co17) magnetic properties in the low temperature sintering condition. Sm2Co17, which is utilized in this research, is synthesized via the sol–gel process at sintering temperatures of 400, 500, and 600 °C. Subsequently, the crystallites indicate the formation of a single-phase Sm2Co17 on all the samples in all temperature variations. Moreover, the peaks in the X-ray diffraction analysis of crystallite sizes calculated using the Scherrer equation are 17.730, 15.197, and 13.296 nm at 400, 500, and 600 °C. Through scanning electron microscopy, the particles are found to be relatively large and agglomerated, with average sizes of 143.65, 168.78, and 237.26 nm. The functional groups are also analyzed via Fourier-transform infrared spectroscopy, which results in the appearance of several bonds in the samples, for example, alkyl halides, alkanes, and esters with aromatic functional groups on the fingerprint area and alkynes, alkyl halides, and alcohol functional groups at a wavelength of above 1500 cm. The test results of the magnetic properties using vibrating-sample magnetometer (VSM) revealed high coercivity and retentivity in the samples sintered at 400 °C. However, the highest saturation occurs in the samples sintered at 600 ℃. At a low sintering temperature (below 1000 °C), samarium cobalt shows as the soft magnetic material. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 


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