共查询到20条相似文献,搜索用时 0 毫秒
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HUANG Yanhong Lü Huibin HE Meng ZHAO Kun CHEN Zhenghao CHENG Bolin ZHOU Yueliang JIN Kuijuan DAI Shouyu & YANG Guozhen Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China 《中国科学G辑(英文版)》2005,48(3)
Since the discoveries of high Tc superconductors and colossal magnetoresistance, enormous efforts have been devoted to investigating the perovskite oxide materials. The fabrication of artificial crystalline materials through layer-by-layer epitaxial growth with full control over the composition and structure at the atomic level has become one of the most exciting areas of research in condensed matter physics and materials science. In related research, much attention has been paid to the new de… 相似文献
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Leng Liao Kui-juan Jin Hui-bin Lu Peng Han Meng He Guo-zhen Yang 《Solid State Communications》2009,149(23-24):915-918
The dynamic process of photoelectric effects in the La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 heterostructure is theoretically revealed by solving equations consisting of time dependent drift–diffusion, Richardson thermionic emission current, and Shockley–Read–Hall recombination. The calculated time dependent evolution of photovoltage and the variation of carrier concentration are obtained. Present results indicate that a smaller parallel resistance should result in faster photoelectric response, but reduce the peak value of the photovoltage in a La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 heterojunction. In addition, the increase of the carrier mobilities induced by applying higher energy photons can decrease the rise time but increase the peak value of the photovoltage. 相似文献
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V. S. Gaviko V. E. Arkhipov A. V. Korolev V. E. Naish Ya. M. Mukovskii 《Physics of the Solid State》1999,41(6):969-973
A study is made of phase transitions in doped La0.9Sr0.1MnO3 compounds using combined x-ray, electrical, and magnetic measurements. Structural phase transitions are observed accompanied
by a change in the cell volume at temperatures of 100–110 K and 300–340 K. These structural changes are found to be related
to different contributions of the rhombic Jahn-Teller Q
2 mode to the formation of the crystal lattice. The structural transition at 100–110 K is accompanied by distinctive magnetic
and electrical properties. The data are analyzed in detail.
Fiz. Tverd. Tela (St. Petersburg) 41, 1064–1069 (June 1999) 相似文献
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The absorption edge of the perovskite La0.9Sr0.1MnO3, determined using the diffuse reflection coefficient spectra, shifts by the giant amount 0.4 eV in the direction of lower
energies as the temperature decreases from the Curie point (155 K) to 141 K.
Pis’ma Zh. éksp. Teor. Fiz. 70, No. 4, 303–306 (25 August 1999) 相似文献
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The electron paramagnetic resonance g factors and the local structure for Ni3+ in LaAl0.9Ni0.1O3 (LAN), La0.75Y0.25Al0.99Ni0.01O3 (LYAN) and YAl0.9Ni0.1O3 (YAN) are theoretically studied from the perturbation formulas of the g factors for a 3d7 ion of low spin (S = 1/2) in tetragonally elongated octahedra. In these formulas, the contributions to the g factors from the tetragonal distortion, characterized by the tetragonal field parameters Ds and Dt are taken into account. According to the calculations, the ligand octahedra around Ni3+ are suggested to suffer 2% relative elongation along the [001] (or C4) axis due to the Jahn-Teller effect. 相似文献
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V. Zakhvalinskii A. Laskhul E. Lähderanta M. Savitskiy E. Pilyuk M. Shakhov 《Physics of the Solid State》2013,55(2):309-313
La0.7Sr0.3Mn0.9Cu0.1O3 ceramic samples have been obtained by the conventional method of the solid-phase reaction, and their resistivity ρ has been investigated in a temperature range from 50 to 300 K in magnetic fields B = 0–20 T. Dependences are typical of perovskite manganites with a maximum at T max = 140–150 K and an increase in ρ near T max with increasing external magnetic field B. It has been established that the behavior of resistivity is caused by the variable range hopping conduction mechanism ρ(T) = ρ0(T)exp[(T 0/T)1/4], where ρ0(T) ~ T 25/4. The Mott variable range hopping conduction has been observed below the Curie temperature for La0.7Sr0.3Mn0.9Cu0.1O3 samples (T C ~ 300 K) in a temperature range from 300 to 200 K. The influence of Cu doping on the properties of La0.7Sr0.3MnO3 samples is apparently caused by an additional distortion introduced into the crystal lattice of the material and by a weakening of the double-exchange mechanism. 相似文献
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《Journal of magnetism and magnetic materials》2005,295(2):168-173
The magnetic and electronic ground states of the polycrystalline perovskite compound La0.7Sr0.3Co0.9Mn0.1O3 have been studied using AC susceptibility, resistivity and neutron depolarization techniques. Results of neutron depolarization study establish the existence of ferromagnetic domains of ∼3 μm size below 180 K. The substitution of 10 at% Mn ions at the Co site in the compound La0.7Sr0.3CoO3 reduces the effective eg electron transfer and suppresses the double exchange interaction. The competition between the reduced ferromagnetic double exchange interaction and the coexisting antiferromagnetic interaction along with the random nature of substitution leads to a randomly canted ferromagnetic ground state for the substituted compound. Resistivity study confirms that the randomly canted ferromagnetic ground state is insulating. 相似文献
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V. E. Arkhipov V. E. Startsev V. P. Dyakina J. Klamut Ya. M. Mukovskii A. Czopnik 《JETP Letters》1998,68(1):42-46
Magnetization measurements were performed on a lanthanum manganite La0.9Sr0.1MnO3 single crystal in the temperature interval 4.2–300 K and magnetic field interval 50 Oe-55 kOe in two sample cooling regimes:
1) cooling down to 4.2 K in a high (55 kOe) magnetic field, and 2) cooling in a “zero” field. It is shown that the temperature
dependences of the magnetization M(T) are substantially different in these regimes. Pronounced anomalies of M(T) were observed at temperatures T*=103 K and T
c
=145 K. The first anomaly is attributed to a structural transition, while the second one corresponds to a ferromagnet-paramagnet
phase transition. The magnetization of a La0.9Sr0.1MnO3 single crystal in the cooling regimes studied shows typical “spin-glass” behavior.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 39–43 (10 July 1998) 相似文献
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Ag掺杂对La0.7Ca0.2Sr0.1MnO3室温磁电阻效应的增强 总被引:1,自引:0,他引:1
本文采用固相反应法制备了一系列La07Ca0.2Sr0.1MnO3/Ag复合物样品,分别测量了样品的XRD图、电阻-温度曲线、磁化强度-温度曲线及磁电阻随温度、磁场的变化关系.实验结果表明,金属Ag颗粒均匀地填隙在La0.7Ca0.2Sr01MnO3晶界处,没有与母体La0.7Ca02Sr0.1MnO3发生反应.该系列样品的金属-绝缘体转变温度Tp及居里温度Tc与LCSMO的Tp及Tp保持一致,没有受到Ag填隙原子的影响.值得注意的是室温下的磁电阻效应显著增强,当Ag掺杂量为25%时,磁电阻效应分别达到23%(316 K,0.3 T)和40%(303 K,2.5 T).这是因为填隙在La07Ca0.2Sr01MnO3晶界上的Ag有效地改善了晶粒边界,使得磁电阻效应增强. 相似文献
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Ba(0.9)Sr(0.1)TiO(3) (BST)-based and PbZr(0.4)Ti(0.6)O(3)-based quasi-periodic multilayers consisting of dense and porous ferroelectric layers have been fabricated by solgel technique using chemical solutions containing polyethylene glycol (PEG) or polyvinylpyrrolidone k30 (PVP). All multilayers exhibit good performance as dielectric mirrors. For each multilayer, the maximum peak reflectivity is over 90% and the photonic stopband width is no less than 30 nm at room temperature. The reflection-band position can be easily tuned by varying the thickness of the bilayer. With the same processing conditions and number of periods, the Bragg reflection performance is almost the same for quasi-periodic PZT multilayers derived from two precursors containing different polymers. The BST multilayers deposited by using a PVP-containing precursor are superior in optical properties, including peak reflectivities and stop-band width, to those deposited by using the PEG-containing solution. 相似文献
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Transport properties and anomalous fatigue effect of Ag/Bi0.9La0.lFeO3/La0.7Sr0.3MnO3 heterostructures 下载免费PDF全文
The transport properties and fatigue effect of Ag/Bi0.9La0.lFeO3/La0.7Sr0.3MnO3 heterostructures are described. By examining the I-V curves, an anomalous fatigue effect was found and its influences on resistive states were studied. I-V curves combined with C-f spectra were used to directly analyze the transport properties and fatigue effect. Compared to the first I-V cycle state, this structure shows more than one order increase of resistance after 100 cycles of "I-V curve training". The redistribution of oxygen vacancies in the depletion layer of Ag/Bi0.9La0.lFeO3 is believed to be responsible for the different resistance mechanisms and tenfold magnitude drop in resistance. The resistive switching is understood to be caused by electric field-induced carrier trapping and detrapping, which changes the depletion layer thickness at the Ag/Bi0.9La0.lFeO3 interface. 相似文献
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利用传统的固相反应分别在1250℃,1300℃,1350℃.烧结条件下制备出钙钛矿结构的La0.9Sr0.1FeO3陶瓷样品.样品的XRD粉末衍射结果显示不同烧结温度的La0.9Sr0.1FeO3陶瓷样品都是单相的正交结构,同时晶胞体积随着烧结温度的升高而减小.从样品的SEM结果看出,随着烧结温度的升高,晶粒逐渐变大,并且晶粒间的空隙逐渐减小,样品更加致密.在室温到800℃的
关键词:
铁酸镧陶瓷
热电性能
烧结温度 相似文献
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Aleksandra Mielewczyk-Gryn Tomasz Lendze Katarzyna Gdula-Kasica Piotr Jasinski Andrzej Krupa Boguslaw Kusz Maria Gazda 《Central European Journal of Physics》2013,11(2):213-218
A composite of CaTi0.9Fe0.1O3 and electrolyte material, i.e. magnesium doped La0.98Mg0.02NbO4 was prepared and studied. The phase content and the sample microstructure was examined by an X-ray diffraction method and scanning electron microscopy. EDS measurements were done both for composite samples and the diffusion couple. The electrical properties were studied by four terminal DC method. The high-temperature interaction between the two components of the composite has been observed. It has been suggested that lanthanum diffused into the perovskite phase and substituted for calcium whereas calcium and niobium formed the Ca2Nb2O7 pyrochlore phase. At 1500°C very large crystallites of the pyrochlore were observed. Regardless of strong interaction between the composite components, its total conductivity was weakly dependent on the sintering temperature. 相似文献