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41.
采用固相反应法,制备了不同成分的稀释磁性半导体Sn1-xMnxO 2(x=002,004,006).利用x射线衍射和傅里叶变换红外光谱法证明 了锰均匀地掺杂到二氧化锡中.在室温下研究了掺锰二氧化锡基稀释半导体的磁性,发现它具有明显的铁磁性 ,同时对磁性的强弱与锰的含量和烧结温度的关系作了研究.
关键词:
稀释磁性半导体
掺杂
烧结
铁磁性
1-xMnx O2')" href="#">Sn1-xMnx O2 相似文献
42.
Qi-Ye Wen Huai-Wu Zhang Yuan-Qiang Song 《Journal of magnetism and magnetic materials》2009,321(19):3110-3113
Pure and Co-doped single-phase CeO2 crystals were synthesized by a solid-state reaction method. Samples of different oxygen vacancy concentration were studied, including (1) as-sintered crystals, (2) powders ground from the same crystal, and (3) a cold-pressed pellet from the ground powder that was unannealed and annealed at 800 °C. By analyzing the magnetic behaviors, surface/volume ratio and O vacancy concentration, the effects of oxygen vacancies on the room-temperature ferromagnetism (RT-FM) of Co-doped CeO2 were systematically investigated. The results confirm that the RT-FM observed in Co-doped CeO2 has a direct relationship with the oxygen vacancy concentration, and support the oxygen vacancy mediated FM mechanism. 相似文献
43.
金红石TiO_2晶体先在真空中进行退火处理,随后在1173 K的氧气中进行不同时间(2 h、5 h、8 h)的热处理.理论上,通过Doppler程序计算了晶体中存在单空位、双空位和间隙O原子时的正电子湮没寿命.实验上,利用正电子湮没寿命谱仪、符合多普勒能谱仪和超导量子干涉仪分别表征了氧气退火后晶体内部的缺陷结构和常温铁磁性.分析结果得出:真空退火晶体的常温铁磁性主要与O空位的存在相关联;而经过氧气退火后,虽然极大地减少了氧空位,但晶体中却产生了大量的Ti双空位,这使得晶体的常温铁磁性有所增加. 相似文献
44.
计算钛空位(VTi)和氧空位(VO)共存情况下未掺杂金红石TiO2的铁磁性.发现VO可以产生局域磁矩,由它引起的自旋极化比VTi引起的更加局域,导致VO之间的铁磁耦合作用弱于VTi之间的铁磁耦合作用.VTi之间的铁磁耦合在引入VO之后进一步加强.VO引入的电子调制两个分离的VTi之间的长程铁磁耦合.加入VTi之后,两个VO的磁矩猝灭,当VO的数量多于VTi的数量二倍时,VO会对磁矩有贡献.结果与实验发现的VO可以提高铁磁有序,并且总的磁矩会随着VO数量的增多而增加的结果符合很好. 相似文献
45.
A new sol-foam-gel method was developed to fabricate La-doped BiFeO3 muttiferroic materials. It was demonstrated that a gradual increase in the content of La-doped into BiFeO3 results in its structure changing from rhombohedral to orthorhombic. A study of other property changes indicates that La-doping in BiFeO3 enhances its ferromagnetism and ferroelectricity. A temperature-dependent magnetization study suggests that the magnetic property of La-doped BiFeO3 samples varied from antiferromagnetic to ferromagnetic as the content of La-doped into BiFeO3 increased from 0 to 20%. Unique temperature-dependent zero field cooling (ZFC) and field cooling (FC) magnetization behaviors were observed in 15% La-doped BiFeO3 -- its ZFC temperature-dependent magnetization being ferromagnetic and its FC temperature- dependent magnetization being antiferromagnetic. A possible mechanism of such an interesting M-T behavior is discussed. 相似文献
46.
In this paper, we report theoretical investigations of structural, electronic and magnetic properties of ordered dilute ferromagnetic semiconductors Cd1−xFexS with x=0.25, 0.5 and 0.75 in zinc blende (B3) phase using all-electron full-potential linear muffin tin orbital (FP-LMTO) calculations within the density functional theory and the generalized gradient approximation. The analysis of band structures, density of states, total energy, exchange interactions and magnetic moments reveals that both the alloys may exhibit a half-metallic ferromagnetism character. The value of calculated magnetic moment per Fe impurity atom is found to be 4 μB. Moreover, we found that p-d hybridization reduces the local magnetic moment of Fe from its free space charge value of 4 μB and produces small local magnetic moments on Cd and S sites. 相似文献
47.
In this article,we investigate the equations of magnetostatics for a configuration where a ferromagnetic material occupies a bounded domain and is surrounded by vacuum.Furthermore,the ferromagnetic law takes the form B=μ0μr(|H|)H,i.e.,the magnetizing field H and the magnetic induction B are collinear,but the relative permeability μr is allowed to depend on the modulus of H.We prove the well-posedness of the magnetostatic problem under suitable convexity assumptions,and the convergence of several iterative methods,both for the original problem set in the Beppo-Levi space W1(R3),and for a finite-dimensional approximation.The theoretical results are illustrated by numerical examples,which capture the known physical phenomena. 相似文献
48.
Preparation and the physical properties of antiperovskite-type compounds Cd1_xInxNNi3(n〈x〈0.2)and Cd1-yCuyNNi3(0〈y〈0.2) 下载免费PDF全文
Two series of Cdl-xInxNNi3 (0 〈 x 〈 0.2) and Cd1_yCuyNNi3 (0 〈 y 〈 0.2) samples were prepared from CdO, In203, CuO, and nickel powders under NH3 atmosphere at 773 K. The structural and physical properties were investigated by means of X-ray powder diffraction temperature-dependent resistivity and magnetic measurements. X-ray powder diffraction results showed that the Cd1-xInxNNi3 and Cd1_yCuyNNi3 compounds have a typical antiperovskite structure, and the CdNNi3, Cd0.9In0.1NNi3, and Cd0.9Cu0.1NNia compounds show metallic temperature-dependent resistivity and exhibit a Fermi liquid behavior at low temperature. In contrast to the paramagnetism previously reported, the CdNNi3 sample exhibits very soft and weak ferromagnetism, and no superconductivity was found in the Cd1-xInxNNi3 and Cdl-yCuyNNi3 samples down to 2 K. Each sample exhibited very soft and weak ferromagnetism, and the temperature dependence of the magnetization of the Cd1-xInxNNi3 and Cd1_yCuyNNi3 samples can be well fitted to the combination of a Bloch term and a Curie-Weiss term. 相似文献
49.
BisFe1-xCoxTi3O15 (x=0.0, 0.2, 0.4, 0.5, 0.6, and 0.8) multiferroic ceramics are synthesized in two steps using the solid state reaction technique. X-ray diffraction patterns show that the samples have four-layer Aurivillius phases. At room temperature (RT), the samples each present a remarkable coexistence of ferromagnetism (FM) and ferroelectricity (FE). The remnant polarization (2Pr) reaches its greatest value of 14 gC/cm2 at x = 0.6. Remnant magnetization (2Mr) first increases and then decreases, and the greatest 2Mr is 7.8 menu/g when x = 0.5. The magnetic properties for x = 0.4 are similar to those for x = 0.6, indicating that the magnetic properties originate mainly from the coupling between Fe3+ and Co3+ ions, rather than from their own magnetic moments. 相似文献
50.
Preparation and the physical properties of antiperovskite-type compounds Cd<sub>1-x</sub>In<sub>x</sub> NNi<sub>3</sub>(0 ≤x≤ 0.2) and Cd<sub>1-y</sub>Cu<sub>y</sub>NNi<sub>3</sub>(0≤y≤0.2) 下载免费PDF全文
Two series of Cd1-xInx NNi3(0 ≤x≤ 0.2) and Cd1-yCuyNNi3(0≤y≤0.2) samples were prepared from CdO, In2O3 , CuO, and nickel powders under NH3 atmosphere at 773K. The structural and physical properties were investigated by means of X-ray powder diffraction temperature-dependent resistivity and magnetic measurements. X-ray powder diffraction results showed that the Cd 1 x In x NNi 3 and Cd 1 y Cuy NNi 3 compounds have a typical antiperovskite structure, and the CdNNi3, Cd0.9 In 0.1 NNi3 , and Cd0.9Cu0.1NNi3 compounds show metallic temperature-dependent resistivity and exhibit a Fermi liquid behavior at low temperature. In contrast to the paramagnetism previously reported, the CdNNi 3 sample exhibits very soft and weak ferromagnetism, and no superconductivity was found in the Cd 1 x In x NNi 3 and Cd 1 y Cu y NNi 3 samples down to 2 K. Each sample exhibited very soft and weak ferromagnetism, and the temperature dependence of the magnetization of the Cd 1-xInx NNi 3 and Cd1-y Cu y NNi 3 samples can be well fitted to the combination of a Bloch term and a Curie–Weiss term. 相似文献