scholarly journals Microstructure and Magnetic Properties of NdFeB Films through Nd Surface Diffusion Process

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Wenfeng Liu ◽  
Mingang Zhang ◽  
Kewei Zhang ◽  
Yuesheng Chai

Ta/Nd/NdFeB/Nd/Ta films were deposited by magnetron sputtering on Si (100) substrates and subsequently annealed for 30 min at 923 K in vacuum. It was found that the microstructure and magnetic properties of Ta/Nd/NdFeB/Nd/Ta films strongly depend on the NdFeB layer thickness. With NdFeB layer thickness increasing, both the grain size and the strain firstly reduce and then increase. When NdFeB layer thickness is 750 nm, the strain reaches the minimum value. Meanwhile, both the in-plane and perpendicular coercivities firstly drastically increase and then slowly decrease with NdFeB layer thickness increasing. The highest in-plane and perpendicular coercivities can be obtained at NdFeB layer thickness of 750 nm, which are 21.2 kOe and 19.5 kOe, respectively. In addition, the high remanence ratio (remanent magnetization/saturation magnetization) of 0.87 can also be achieved in Ta/Nd/NdFeB (750 nm)/Nd/Ta film.

2016 ◽  
Vol 30 (08) ◽  
pp. 1650126
Author(s):  
Yudong Fu ◽  
Feng Yan ◽  
Xiaoshuo Zhu ◽  
Xiaoxue Feng ◽  
Zaizai Guo

The paper was presented to study the microstructure and magnetic properties of Mo/[NdFeB/Mo] × 10/Mo multilayered films prepared by magnetron sputtering on Si(100) substrate. The SEM observation of microstructure showed that the specimen had fine multilayer structure and the NdFeB layers were successfully separated by Mo layers on the cross-section. The interface between the NdFeB and Mo layer disappeared after annealing. X-ray diffraction patterns of the annealed films revealed that there are a large amount of Nd2Fe[Formula: see text]B phases. The thickness of Mo layer had obvious effects on magnetic properties of the samples. When it reached 21 nm, the number and the intensity of NdFeB phase increase, and the remanent magnetization ratio Mr/Ms suddenly rise. The influences of annealing on surface morphology and microstructure of NdFeB thin films were also studied.


2012 ◽  
Vol 512-515 ◽  
pp. 1408-1411
Author(s):  
Qing Kai Xing ◽  
Zhi Jian Peng ◽  
Cheng Biao Wang ◽  
Zhi Qiang Fu ◽  
Xiu Li Fu

Mn-Zn ferrites with different doping contents of W6+ ions were prepared by using standard ceramic technique. The microstructure and magnetic properties of the as-prepared Mn-Zn ferrites were investigated. It was found that all the samples with different contents of W6+ ions consisted of ferrite phase of typical spinel cubic structure. With increasing doping content of W6+ ions, the lattice constant of the ferrites decreased but the grain size increased. Through the measurement of magnetic properties, it was revealed that the saturation magnetization and initial permeability of the samples increased with small doping content of W6+ ions but decreased with additional doping, and the Curie temperature decreased monotonously with W6+ ion doping.


2013 ◽  
Vol 690-693 ◽  
pp. 1702-1706 ◽  
Author(s):  
Shuang Jun Nie ◽  
Hao Geng ◽  
Jun Bao Wang ◽  
Lai Sen Wang ◽  
Zhen Wei Wang ◽  
...  

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%.


2010 ◽  
Vol 654-656 ◽  
pp. 1106-1109
Author(s):  
Ya Qiong He ◽  
Chang Hui Mao ◽  
Jian Yang

Nanocrystalline Fe-Co alloy powders, which were prepared by high-energy mechanical milling, were nitrided under the mixing gas of NH3/H2 in the temperature range from 380°C to 510°C. X-ray diffraction (XRD) was used to analyze the grain size and reaction during the processing. The magnetic properties of the nitrided powders were measured by Vibrating Sample Magnetometer (VSM). The results show that with the appearance of Fe4N phase after nitride treatment, and the grain-size of FeCo phase decreases with the increase of nitridation temperature between 380°C to 450°C.The saturation magnetization of nitrided alloy powder treated at 480°C is about 18% higher than that of the initial Fe-Co alloy powder, accompanied by the reduction of the coercivity. Transmission electron microscope (TEM) was used, attempting to further analyze the effect of Fe4N phase on microstructure and magnetic properties of the powder mixtures.


2010 ◽  
Vol 160-162 ◽  
pp. 1787-1790
Author(s):  
Jing Cao ◽  
Yong Feng Wang ◽  
Chun Xue Wei

1J79 alloy was prepared by vacuum electric arc smelting.The crystal growth and the content of impurity was observed by electron probe microanalyzer,and magnetic properties were measured by vibrating sample magnetometer(VSM).Experimental results show that inclusions in the alloy are fewer and fewer, composition becomes more uniform with the increases of the Mo content, and grain size also becomes larger and larger with the increases of Mo content, to reduce coercivity. The small amount of Mo addition is useful to improve the saturation magnetization and reduce coercivity.


2020 ◽  
Vol 20 (5) ◽  
pp. 2998-3003
Author(s):  
Jia Liu ◽  
Zhou Wang ◽  
Yanyan Wang

A novel type of magnetic Fe2O3/Fe3O4 heterogeneous microparticles with ellipsoidal macropores was prepared via the ethanol-water reflux and rapid combustion process. The experimental results showed that the volume of absolute ethyl alcohol and the calcination temperature were the key factors to the grain sizes and the magnetic properties, the calcination temperature largely affected the saturation magnetization and the grain size of Fe2O3/Fe3O4 heterogeneous microparticles, and the amount of absolute ethyl alcohol also tremendously affected the saturation magnetization, however, the amount of absolute ethyl alcohol affected little on the grain size. Fe2O3/Fe3O4 heterogeneous microparticles calcined at 200 °C for 1 h with absolute ethyl alcohol of 20 mL had the largest saturation magnetization of 90.1 Am2/kg.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1383-1388 ◽  
Author(s):  
MASLEEYATI YUSOP ◽  
DELIANG ZHANG ◽  
MARCUS WILSON ◽  
NICK STRICKLAND

Al 2 O 3-20 vol % Fe 70 Co 30 composite powders have been prepared by high energy ball milling a mixture of Al 2 O 3 powder and Fe 70 Co 30 alloy powder. The Fe 70 Co 30 alloy powder was also prepared by mechanical alloying of Fe and Co powders using the same process. The effects of milling duration from 8 to 48 hours on microstructure and magnetic properties of the nanostructured composite powders have been studied by means of X-ray Diffractometry (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). It was found that the nanostructured composite powder particles with irregular shapes and Fe 70 Co 30 alloy particles being embedded in them formed after 8 hours of milling. The average grain size of the Al 2 O 3 matrix reduced drastically to less than 18nm after 16 hours of milling. On the other hand, the embedded alloy particles demonstrated almost unchanged average grain size in the range of 14-15nm. Magnetic properties of the powder compacts at room temperature were measured from hysteresis curves, and show strong dependence of the milling time, with the coercivity increasing from 67.1 up to 127.9kOe with increasing the milling time from 8 to 48 hours. The possible microstructural reasons for this dependence are discussed.


2019 ◽  
Vol 34 (01) ◽  
pp. 2050002
Author(s):  
Wei Zhang ◽  
Aimin Sun ◽  
Xiqian Zhao ◽  
Xiaoguang Pan ◽  
Yingqiang Han

Manganese substituted nickel–copper–cobalt ferrite nanoparticles having the basic composition [Formula: see text] (x = 0.0, 0.1, 0.2, 0.3 and 0.4) were synthesized by sol–gel auto-combustion method. X-ray diffraction (XRD) was used to estimate phase purity and lattice symmetry. All the prepared samples show the single-phase cubic spinel structure. Fourier transform infrared (FTIR) measurements also confirm the cubic spinel structure of the ferrite that is formed. The preparation of samples show these nearly spherical particles by Transmission electron microscopy (TEM). The magnetic properties of Mn[Formula: see text] ion substituted in nickel–copper–cobalt ferrite were studied by Vibrating sample magnetometer (VSM). The saturation magnetization ([Formula: see text]), remanent magnetization [Formula: see text], coercivity [Formula: see text], magnetic moment [Formula: see text] and anisotropy constant [Formula: see text] first increase and then decrease with the increase of [Formula: see text] ions content. They had better magnetism than pure sample and other substituted samples when the substitution amount of [Formula: see text] ions was [Formula: see text]. At [Formula: see text], the maximum values of remanent magnetization [Formula: see text], saturation magnetization [Formula: see text] and coercivity [Formula: see text] are 25.58 emu/g, 61.95 emu/g and 689.76 Oe, respectively. This indicates that the magnetism of ferrite can improve by substituting with the appropriate amount of manganese. However, due to the excess [Formula: see text] ions instead, ferrite magnetism is weakened. This means that these materials can be used in magnetic data storage and recording media.


2014 ◽  
Vol 28 (06) ◽  
pp. 1450043 ◽  
Author(s):  
Shuyun Wang ◽  
Yuanmei Gao ◽  
Tiejun Gao ◽  
Yuan He ◽  
Hui Zhang ◽  
...  

A series of Ta (4 nm)/ ZnO (t nm )/ Ni 81 Fe 19 (20 nm)/ ZnO (t nm )/ Ta (3 nm) magnetic thin films were prepared on lower experimental conditions by magnetron sputtering method. Effects of ZnO layer thickness and substrate temperature on anisotropic magnetoresistance and magnetic properties of these Ni 81 Fe 19 films have been investigated. The experiment results show that the anisotropic magnetoresistance value of the Ni 81 Fe 19 film is enhanced with the increasing of the inserted ZnO layer thickness. When the ZnO thickness is 2 nm, the anisotropic magnetoresistance value achieves the maximum. In addition, the anisotropic magnetoresistance of the Ni 81 Fe 19 film is also enhanced with the increasing of substrate temperature, and when the temperature is 450°C, the anisotropic magnetoresistance reaches the maximum. The anisotropic magnetoresistance value of 20 nm Ni 81 Fe 19 films with 2 nm ZnO layer can achieve 3.63% at 450°C which is enhanced 11.6% compare with the films without ZnO layer.


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