Magnetic properties and microstructures of SnO_2 doped Mn-Zn ferrites

The effects of additive SnO2 (0.4wt.%), with and without SiO2 (0.02wt.%) and/or CaO (0.04wt.%), on the microstructure and magnetic properties of Mn-Zn ferrites were reported. The results reveal that SnO2 on its own increases the initial permeability (μi) slightly, but SnO2 with SiO2 and/or CaO decreases the values of μi. However, ferrites with SnO2 additions have reduced power losses. The separate contributions of hysteresis loss and eddy current loss to the total power loss show that SnO2 (with or without SiO2 and/or CaO) doping increases the hysteresis loss slightly, but SnO2 doping alone reduces the eddy current loss significantly (～14%). The additions of SiO2 or CaO further decrease the eddy current loss, and by interaction of SnO2-CaO-SiO2, the eddy current loss is reduced by more than 20%. These magnetic and microstructural effects were discussed in terms of the additive-impurity interaction, the existence of grain boundary phases, and the effective bulk and grain boundary resistivities of the ferrites.

Preparation and Characterization of La Doped Ferrite Using Marine Manganese Nodules as Raw Materials

A kind of La doped ferrite was prepared with marine manganese nodules derived from East Pacific sea-bottom as raw material, NaOH as fluxing reagent, La(NO3)3 as doping agent, by calcination at 1000 ℃ for 5 h. XRD analysis showed that the ferrite products were of a spinel structure, and that its molecular formula could be expressed as MnFe2-xRxO4. SEM images proved that these ferrites showed octahedral and cubic aspects. It was found that there is some relationship between the La doping amount and the magnetic property of the ferrite. When the La doping amount was 0.03, the susceptibility of the ferrite was maximal. The as-prepared La doped ferrite is a kind of soft magnetic material that is easy to be magnetized with rather weak coercive force.

Effects of Ce^(3+) doping on the structure and magnetic properties of Mn-Zn ferrite fibers

Ce3+-doped Mn-Zn ferrite fibers were successfully prepared by the organic gel-thermal decomposition method from metal salts and citric acid. The composition,structure,and magnetic properties of these ferrite fibers were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and vibrating sample magnetometer (VSM). The results show that Mn0.2Zn0.8Fe2-xCexO4 (x = 0-0.04) fibers are featured with an average grain size of 11.6-12.7 nm,with diameters ranging between 1.0 to 3.5 μm and a high ...

Effect of Nd Doping on Nanosized Mn-Zn Ferrite

Nanosized Mn-Zn ferrite doped with Nd (Mn_ 0.6Zn_ 0.4Nd_xFe_ 2-xO_4) were fabricated by hydrothermal precipitation route and studied by XRD, TEM, DSC and VSM. The effects of Nd doping on manganese zinc ferrites were discussed. The results show that the samples with a small amount of Nd doping are spinel crystal structure and uniformly nanosized particles with little aggregation. DSC analysis of Mn_ 0.6Zn_ 0.4Fe_2O_4 and Mn_ 0.6Zn_ 0.4Nd_ 0.06Fe_ 1.94O_4 samples both present two exothermic peaks ascribed to the redistribution of Mn 2+, Zn 2+ and Fe 3+ ions in the two sub-lattices (tetrahedral (A) and octahedral (B) sites), and the oxidation of Mn 2+-ions at higher temperatures respectively. The saturation magnetization (M_s) for Mn_ 0.6Zn_ 0.4Nd_xFe_ 2-xO_4 ferrites increase with (x) up to 0.06 and decrease for higher concentrations. And supermagnetic behavior was observed at 25 ℃ in the M-H loops of Mn_ 0.6Zn_ 0.4Fe_2O_4 and Mn_ 0.6Zn_ 0.4Nd_ 0.06Fe_ 1.94O_4 samples for their extremely small sizes.

低温烧结Mn掺杂Mg-Cu-Zn铁氧体研究

利用溶胶 -凝胶自燃烧法合成了一系列低温烧结 Mn掺杂 Mg- Cu- Zn铁氧体 (Mg0 .2 Cu0 .2 Zn0 .6 O) (Fe2 - xMnx O3) 0 .97(x=0 ,0 .0 1,0 .0 3,0 .0 5 ,0 .0 7)。该文对低温烧结 Mn掺杂 Mg- Cu- Zn铁氧体的成相 ,致密化过程及锰含量对其磁性能和显微结构的影响进行了研究。研究发现 ,具有较低磁致伸缩系数的 Mg- Cu- Zn铁氧体呈现出比Ni- Cu- Zn铁氧体更好的磁性能。因此 ,低温烧结的 Mg- Cu- Zn铁氧体有望替代 Ni- Cu- Zn铁氧体而用作多层片式电感材料。在一定 Mn掺杂范围内 ,Mn掺杂对 Mg- Cu- Zn铁氧体磁性能的改进 ,主要是通过其对材料内部磁致伸缩系数和内应力的调控来实现的 ,而不是通过对微观结构的影响而获得的。

Microwave electromagnetic and absorbing properties of Dy^(3+) doped MnZn ferrites

Dy3+ doped Mn-Zn ferrites Mn0.3Zn0.7Fe2-xDyxO4(x=0,0.01,0.02,0.03,0.04)were prepared by the conventional solid-state reaction.The crystal structure,surface morphology and electromagnetic properties of the calcined samples were characterized by X-ray diffraction analysis(XRD),scanning electron microscopy(SEM) and network analyzer(Agilent 8722ET).All the XRD patterns showed the single phase of the spinel-type ferrite without other intermediate when x≤0.03.The average crystallite size was about 44?56 nm.The mi...

镧系元素掺杂Mn-Zn铁氧体的制备和研究

本文以Fe2(SO4)3、ZnSO4·7H2O、MnSO4·H2O和Ln(NO3)3(Ln=La、Ce、Nd)为原料,通过水热合成法制备出了镧系元素(Ln=La、Ce、Nd)掺杂Mn鄄Zn铁氧体(Mn0.6Zn0.4LnxFe2-xO4)超细粉末,并利用XRD、TEM和VSM等手段对样品进行了表征,讨论了Ln掺杂量与掺杂种类对Mn鄄Zn铁氧体样品的影响。结果表明:要得到单相尖晶石型Mn0.6Zn0.4LnxFe2-xO4,Ln掺杂量(x)应小于0.1;适量Ln的掺杂可以大大改善Mn鄄Zn铁氧体的磁性能。

Gd^(3+)掺杂对Mn-Zn铁氧体结构、磁性能和磁热效应的影响

采用化学共沉淀法制备了Gd3+掺杂的Mn-Zn铁氧体微粒,并通过XRD、FTIR、VSM等研究了掺杂量对基体材料结构、磁性能及在外磁场作用下磁热效应的影响．结果表明,适量Gd3+的掺杂可以有效改善Mn-Zn铁氧体的磁性能和磁热效应,成分为Mn0．4Zn0．6Gd0．06Fe1．94O4的铁氧体粉体的粒径约为20nm,具有最高的饱和磁化强度和矫顽力,50mg的该样品与1mL水形成的悬浮液,在频率为60kHz的外磁场诱导下,升温可达31℃,显示出较高的磁热性能,有望作为肿瘤热疗的内加热材料．

高Mn含量对NiZnCu铁氧体性能的影响

研究了在（Ｎｉ０.2Ｃｕ0 .2Ｚｎ0 .６）１．０３（Ｆｅ2Ｏ３)0 ．９７＋０．９７ｘＭnO2(ｘ=０．１～０．５)中，随Ｍｎ含量的变化，磁性能的改变及与微观结构的关系．适量的Ｍｎ掺杂可以提高室温下铁氧体的起始磁导率，而Ｍｎ含量继续增加会促使第二相形成，使磁导率温度系数变大，出现类似铁电体的弛豫现象．

稀土元素掺杂Mn-Zn铁氧体的制备及磁性能

以FeSO4.7H2O、MnSO4.H2O、ZnSO4.7H2O、RE2O3(RE=Y、Nd、Gd、Dy)、HCl为原料,NaOH溶液为沉淀剂、H2O2为氧化剂,采用氧化共沉淀法制备出稀土元素掺杂(RE=Y、Nd、Gd、Dy)Mn-Zn铁氧体(Mn0.5Zn0.5RExFe1-xO4),通过傅里叶变换红外光谱仪(IR),X射线衍射仪(XRD)和振动样品磁强计(VSM)对样品进行表征,讨论了稀土元素掺杂的种类和量对样品的结构和磁性能的影响。结果表明:要得到单相尖晶石结构Mn-Zn铁氧体,稀土元素掺杂量应控制在x≤0.02;Mn0.5Zn0.5RExFe1-xO4的晶粒度随掺杂含量x的增大单调减少;掺杂稀土元素Y、Nd对Mn-Zn铁氧体的磁性有削弱作用,不宜掺杂;而少量的稀土元素Gd、Dy掺杂有利于样品的饱和磁化强度的提高,x=0.02时,其饱和磁化强度分别达到最大值26.5和29.3emu/g。

Mn_(0.2)Zn_(0.8)Fe_(2-x)Ce_xO_4铁氧体纤维的制备、结构及其磁性能

以柠檬酸和金属盐为原料，采用有机凝胶一热分解法成功制备了Mn0.2Zn0．8Fe2-xrCexO4（x=0～0．04）系列铁氧体纤维。通过XRD、SEM和VSM等技术对产物进行了表征，研究了Ce抖掺杂对Mn—Zn铁氧体纤维的结构，微观形貌及磁性能的影响。结果表明，所制得的纤维轴向较为均匀，长径比较大，直径在0．5～3．5μm之间，组成纤维的晶粒平均尺寸为11．6～12．8nm。Ce^3＋掺杂没有引起Mn0.2Zn0．8Fe2-xrCexO4纤维结构的明显变化，仍为单一的立方尖晶石结构，但晶格常数和晶粒粒径随Ce^3＋掺入量的增加而略微增大。Ce抖掺杂使Mn-Zn铁氧体纤维的饱和磁化强度增大，矫顽力下降，软磁性能有所提高。

废旧锌锰电池制备Cu掺杂Mn-Zn铁氧体

以硝酸溶解废旧碱性锌锰电池所得的溶液为原料,以酒石酸为凝胶剂,采用sol-gel法制备出一系列Cu掺杂Mn-Zn铁氧体(Mn0.6–x/2Zn0.4–x/2CuxFe2O4,x=0.1,0.2,0.3和0.4)。经XRD、VSM测试,结果表明:Cu掺杂不仅没有改变Mn-Zn铁氧体的相结构,而且有利于尖晶石结构的形成;Cu掺杂后Mn-Zn铁氧体的Ms、Mr和Hc的变化趋势,都是先增大后减小,最适宜的掺杂量x为0.1。此时,Ms为2.66×105A/m,Mr为5.73×104A/m,Hc为1.6/π×104A/m。

B_2O_3掺杂对纳米Mn-Zn铁氧体烧结性能的影响

针对目前的纳米材料掺杂不均,易导致烧结后材料性能差等问题。本文将掺杂物制成水溶液,然后再与Mn-Zn铁氧体纳米粉体进行混合,以提高B_2O_3分布的均匀度。研究结果表明:随着B_2O_3掺杂量的增加,烧结后材料的各项性能呈抛物线规律变化,并于B_2O_3掺杂量为0.15wt%时达到极值。与未掺杂的材料相比,虽然材料的饱和磁化强度、起始磁导率、居里点及截止频率有不同程度下降,但其功率损耗特性却显著改善。这应得益于B_2O_3的均匀掺杂使得烧结后材料的致密度提高(相对密度约为98%)以及微观组织的改善。

少量钴掺杂对Mn-Zn铁氧体结构和磁性质的影响(英文)

采用溶胶凝胶自燃烧法制备了钴掺杂的Mn-Zn铁氧体,研究了少量钴掺杂对其结构和磁性质的影响。利用X射线衍射仪对制备的粉末测试发现,Mn0.4Zn0.6-xCoxFe2O4系列铁氧体都具有纯净的尖晶石结构。晶格常数和饱和磁化强度都随着钴替代量的增加而增加。μi-T线具有两个磁导率最大的峰值并且磁导率的第二峰值随着钴的增加向低温移动。磁导率的第二峰值的温度可以通过改变钴含量来调节。基于铁氧体中磁晶各向异性补偿模型,阐明了少量钴掺杂对铁氧体磁性质影响的作用机理。

Magnetic properties of samarium and gadolinium co-doping Mn-Zn ferrites obtained by sol-gel auto-combustion method

Mn-Zn ferrites doped with different contents of Sm^（3＋） and Gd^（3＋） ions were prepared by sol-gel auto-combustion method and characterized by Fourier transform infrared spectroscopy（FTIR）, thermogravimetric analysis（TG）, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and vibrating sample magnetometer（VSM）. When samples were calcined in a relatively low temperature below 1100 °C, secondary phases（α-Fe_2O_3） could be identified. Therefore, in order to acquire pure and better crystallinity, the suitable calcining temperature of powders was selected at 1200 °C. It was also found that all the samples consisting of ferrite phases of typical spinel cubic structure and average crystallite sizes between 31.5 and 38.2 nm were obtained after calcining at 1200 oC for 4 h. The lattice parameters increased almost linearly with increasing Sm content. A dense microstructure was obtained after sintering at 1250 °C for 4 h. Through the analysis of magnetic properties, hysteresis loops for all the samples were narrow with low values of coercivity and retentivity, indicating the paramagnetic nature of these samples. And saturation magnetization Ms strongly depended on the type of additive to reach a maximum of 47.99 emu/g for x=0.015, which showed a great promise for hyperthermia applications.

掺杂对高磁导率低损耗锰锌铁氧体材料磁性能的影响

采用氧化物陶瓷工艺制备了高磁导率低损耗锰锌铁氧体材料,研究了Nb2O5掺杂对材料磁性能的影响。结果表明掺杂0.015%(质量分数)Nb2O5的锰锌铁氧体材料具有较好的磁性能:起始磁导率μi=13386,起始磁导率比温度系数αμ/μi=-0.6×10-6/K,相对损耗因数tanδ/μi=3.2×10-6。

镧掺杂对大洋锰结核制备铁氧体磁性的影响

大洋锰结核又称铁锰结核、多金属结核,常见于4000-6000m的海底沉积物表层,在世界各大洋底均有分布,预计总储量超过3×10^12t。天然锰结核含有Mn和Fe,以及Cu、Co、Ni、铂族和稀土等60多种金属元素,其中锰占20%-30%,铁约占3-20%。

电解锰渣制备SiO_2掺杂锰锌铁氧体

本文以电解锰渣为原料,经酸浸、除杂后,采用化学共沉淀法结合高温焙烧法制备了锰锌铁氧体磁粉。通过改变反应温度,研究了共沉淀温度对锰锌铁氧体前驱体合成率的影响。分别用XRD、BET以及VSM对掺杂样品的晶粒结构、比表面积以及磁性能进行了表征。结果表明,当温度为50℃时前驱体合成率最高,达到87.9%;适当的SiO2掺杂可以提高样品的比表面积,当掺杂量为0.45%时,样品的磁性能最佳,其饱和磁化强度为71.95 emu/g,矫顽力为10.49 G,剩余饱和磁化强度为1.32 emu/g。

废旧电池水热法制备镍掺杂纳米晶锰锌铁氧体

以废旧碱性锌锰电池为原料,采用水热法制备了镍掺杂的纳米晶锰锌铁氧体。用XRD、TEM和VSM,就镍掺杂量对锰锌铁氧体的相结构和磁性能的影响进行了研究。结果表明:镍掺杂的摩尔分数为0～2%时,均可制得具有尖晶石结构的纳米晶锰锌铁氧体。最佳x(Ni2+)为1.5%,此时镍掺杂锰锌铁氧体的Ms、Mr和Hc分别为3.6432×105A/m,2.5088×104A/m和2.388×103A/m。

复合掺杂对高磁导率锰锌铁氧体磁性能的影响

用复合掺杂的方法制备了高性能的高磁导率MnZn铁氧体材料。研究了Nb2O5-P2O5复合掺杂对MnZn铁氧体微观结构及磁性能的影响。结果表明,适量的Nb2O5-P2O5复合掺杂有利于促进晶粒均匀致密,提高材料的起始磁导率,降低损耗。在配方中,当ζ(Nb2O5∶P2O5)为2∶8时,起始磁导率可达到11 823。