F. Zhang1)
,
X. D. Sun1)
,
J. You2)
,
Z. Zhang2)
,
L. X. Ding3)and Y. M. Wang3)1) School of Materials and Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China2) Liaoning Analyzing and Testing Research Center
,
Shenyang 110015
,
China3) Department of Materials
,
School of Mechanical Engineering
,
Shenyang University
,
Shenyang 110044
,
China
金属学报(英文版)
Synthesis of a m m oniu m alu min u m carbonate hydroxide ( A A C H) w as investigated usinga m m oniu m alu min u m sulfate and a m moniu m hydro carbonate as the starting m aterials . Itw as found that A A C Hcan be synthesized by adding a m m oniu m alu m inu m sulfate solution torapidly stirred a m moniu m hydro - carbonate solution at a tem perature of 30 ℃. A A C Hcantransfor m to α Al2 O3 co m pletely by calcining at 1100 ℃ for 1 hour , and the obtained po w ders , with a particle size of 100 n m , can be sintered to 98 99 % relative density at 1500 ℃for 2 hours .
关键词:
a m moniu m alu m inu m carbonate hydroxide
,
null
,
null
,
null
Applied Physics Letters
The effect of nonmagnetic Y partial substitution at the Dy site in Dy(1-x)Y(x)MnO(3) up to x=0.2 on magnetism, specific heat, and ferroelectricity is investigated, which resulted in a preliminary multiferroic phase diagram. It is revealed that the Y partial substitution suppresses the Dy-spin ordering point (T(Dy)) and ferroelectric ordering point (T(FE)) but enhances the Mn-spin ordering point (T(N)). The interaction between the spins of Dy and Mn is remarkably affected by Y substitution. The measured electrical polarization depends on the Y substitution in a complex way because the ferroelectricity is sensitive to the interaction between the spins of Dy and Mn. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536506]
关键词:
ferroelectricity;polarization
王龙章
,
黄克雄
,
骆如铁
,
姚渝
,
叶大陆
,
陈新民
金属学报
本文讨论了双金属共存体系M_1-M_2-x-y,当两种金属的化合物相互作用生成多金属化合物时,优势区相图的绘制原理、方法及计算机程序。通过绘制Zn-Fe-SO系的优势区相图,分析了ZnO·Fe_2O_3的生成及稳定条件,并说明了其在硫化锌矿焙烧中的指导作用。
关键词:
M_1-M_2-x-y体系
,
predominance diagram
,
roasting
,
zinc sulfide ore
Philosophical Magazine
The microstructure of ferroelectric [PbZr(x)Ti(1-x)O(3)/PbZr(y)Ti(1-y)O(3)](n) epitaxial multilayers (x/y 0.2/0.4, 0.4/0.6) deposited on SrRuO(3)-coated SrTiO(3) substrates by pulsed-laser deposition with different layer periodicity and layer thickness was characterized by means of transmission electron microscopy. Electron diffraction and contrast analysis revealed a very clear and well-separated layer sequence. The microstructures of PbZr(0.2)Ti(0.8)O(3)/PbZr(0.4)Ti(0.6)O(3) and PbZr(0.4)Ti(0.6)O(3)/PbZr(0.6)Ti(0.4)O(3) multilayers show a similar tendency in the dependence on the individual layer thickness. Whereas with thick individual layers, tetragonal a-domains are confined to specific layers of the two types of multilayers, below a certain critical thickness of the individual layers, a-domains extend over the whole film. This indicates a transition into a uniform tetragonal lattice and strain state of the whole multilayer. Increasing the layer periodicity further, the interfaces in PbZr(0.4)Ti(0.6)O(3)/PbZr(0.6)Ti(0.4)O(3) multilayers become rough, and complex a-domain configurations appear.
关键词:
ferroelectrics;transmission electron microscopy;microstructure;ferroelectric thin-films;misfit relaxation mechanisms;domain;configurations;heterostructures;polarization
Journal of Applied Physics
It has been reported both experimentally and theoretically that the Ba(2+)-doping at the A-site of quantum paraelectric SrTiO(3) suppresses the quantum fluctuations by activating the ferroelectric mode, while the Ru(4+)-doping at the B-site plays the opposite role. For a double-impurity doped SrTiO(3), i. e., Sr(1-x)Ba(x)Ti(1-y)Ru(y)O(3), where the two types of opposite effects compete with each other, we propose an improved transverse-field Ising model in order to investigate the effect of the double-impurity doping on the quantum phase transitions and critical behaviors. The calculated quantum behavior is quite well consistent with experimental measurements. A linear relationship between the quantum critical doping concentrations for Ba(2+) and Ru(4+) is predicted, subsequently validated qualitatively by an anharmonic oscillator model. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3361080]
关键词:
induced phase-transition;srtio3;susceptibility;paraelectrics;batio3;model
罗广圣
,
李小怡
,
周正有
,
刘光华
,
熊惟皓
,
吴小山
中国有色金属学报
采用固相反应法制备La(1.x)2/3Ca1/3MnO3(x=0.0,0.04)和(La0.7Y0.3)2/3Ca1/3MnO3系列样品,测量不同温度下的磁化强度-磁场曲线,计算样品的磁熵变,研究La空位掺杂和Y3+离子掺杂对磁热效应的影响.结果表明,La空位掺杂(x=0.04)的样品在居里温度附近磁熵变最大值为6.22 J/(kg.K),这比La2/3Ca1/3MnO3磁熵变最大值(6.26 J/(kg.K))稍有降低;而Y3+离子掺杂的样品在温度60 K时和磁场强度2 T下,其磁熵变最大值为0.568 J/(kg.K),并且磁熵变随温度变化有继续增大的趋势.这表明(La0.7Y0.3)2/3Ca1/3MnO3可以作为一定温区的磁致冷材料.
关键词:
(La(1-x-y)Yy)2/3Ca1/3MnO3化合物
,
固相反应
,
磁热效应
,
磁熵变
,
空位掺杂
Journal of Alloys and Compounds
(Ca(1-x-y),Ln(y))MoO(4): xEu(3+) (Ln = Y, Gd) red phosphors were prepared by co-precipitation method with NH(4)HCO(3)-NH(3)center dot H(2)O system as the precipitating agent. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), and energy-dispersive X-ray spectrometer (EDS) were used to characterize the structure and composition of the phosphors. The synthesized (Ca(1-x-y),Ln(y))MoO(4): xEu(3+) have scheelite structure with pure phase. FT-IR spectra show strong absorption peaks between 914 and 730 cm(-1) which are assigned to the vibration of O-Mo-O in MoO(4)(2-) tetrahedron. The EDS analysis reveals that the red phosphors have been successfully prepared by co-precipitation method according to theoretic ratio. Photoluminescence spectra show a red emission around 614 with 394 and 464 nm excitation, which is match well with the output wavelength of commercial ultraviolet and blue LED chips. The luminescent intensity of (Ca,Ln)MoO(4): Eu(3+) is obviously higher than that of CaMoO(4): xEu(3+). Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
关键词:
Co-precipitation;Red phosphor;Photoluminescence;(Ca(1-x-y),Ln(y))MoO(4): xEu(3+) (Ln = Y Gd);hydrothermal synthesis;camoo4;eu3+;luminescence
