12008-06-9Relevant articles and documents
Magnetic field dependence of the rare earth B12 icosahedral cluster compound GdB18Si5
Mori, Takao
, p. 2803 - 2807 (2005)
Magnetic field dependence of the rare earth B12 icosahedral cluster compound GdB18Si5 was investigated. GdB 18Si5 is the only system in the rare earth boron icosahedral cluster compounds in which 3 dimensional long range order has been observed. GdB18Si5 exhibits an antiferromagnetic transition at TN = 3.2 K, with the spins antiferromagnetically aligned in-plane, perpendicular to [0 0 1]. The magnetic phase diagram was determined for the field applied along the c-axis. The general magnitude of field corresponds to the temperature scale. An interesting dependence at low magnetic fields was observed when the field was varied in-plane, with a reorientation of the spin, a spin flip, appearing to occur at fields below 300 G.
Single-crystalline GdB6 nanowire field emitters
Zhang, Han,Zhang, Qi,Zhao, Gongpu,Tang, Jie,Zhou, Otto,Qin, Lu-Chang
, p. 13120 - 13121 (2005)
Having the lowest work function in the rare-earth hexaboride family, GdB6 nanowires of rectangular cross-section with about 50 nm in lateral dimension and several microns in length have been successfully produced using a CVD method. The nanowires are grown in the 001 lattice direction, and both the tip-top and the side surfaces are terminated with the {100} lattice planes. A GdB6 single nanowire field emitter has also been built with an emission current of more than 150 nA at an applied field of less than 3.2 V/μm. The work function of the nanowire emitter was estimated to be about 1.5 eV. Copyright
Mg-assisted autoclave synthesis of RB6 (R = Sm, Eu, Gd, and Tb) submicron cubes and SmB6 submicron rods
Zhang, Maofeng,Jia, Ying,Xu, Guogen,Wang, Pengfei,Wang, Xiaoqing,Xiong, Shenglin,Wang, Xuanjun,Qian, Yitai
, p. 1289 - 1294 (2010/08/13)
Submicron crystalline rare-earth hexaborides (RB6; R = Sm, Eu, Gd, and Tb) have been successfully prepared by a facile one-step solid-state reaction of RCl3·OH2O, B2O3, and Mg powder in an autoclave at the relatively low temperature of 500°C. By controlling the reaction, conditions, submicronsized cubes (RB6) and rod- and needlelike SmB6 are obtained. The possible growth mechanism of the 1D SmB6 structures has also been discussed. The XRD patterns of the products show that all of the hexaborides can be indexed to a cubic phase with high crystallinity and high purity. The field-emission scanning electron microscopy (FESEM) and TEM images display their cube-, rod-, and needlelike morphologies. The selected-area electron diffraction (SAED) patterns reveal the single-crystalline nature of the products.
Solar control dispersions and coatings with rare-earth hexaboride nanoparticles
Takeda, Hiromitsu,Kuno, Hiroko,Adachi, Kenji
, p. 2897 - 2902 (2009/02/05)
Nanoparticle dispersions of rare-earth hexaborides have been prepared using a media agitation mill and have been examined for optical properties. High visible light transmittance coupled with strong absorption in the near-infrared (NIR) wavelengths suitable for solar control windows are reported for hexaboride nanoparticle dispersions with particle size dependence and the effect of artifacts. Nanoparticulate LaB6 shows the largest NIR absorption among rare-earth hexaborides. NIR absorption is considered to arise from the free electron plasmon resonance. On decreasing the particle size below 120 nm, both visible light transmittance and NIR absorption are found to increase gradually until the size of 18-26 nm when they reach the maximum, and then decrease again at below 18 nm. Zirconia contamination and formation of lanthanum oxide were found to be involved during the milling process, leading to small additional absorptions around 300 and 650 nm, respectively.
Thermodynamic functions for heavy rare-earth hexaborides as measured by calorimetry in the temperature range from 5 to 300 K
Sirota,Novikov,Vinokurov
, p. 1722 - 1725 (2007/10/03)
The molar heat capacities of gadolinium, terbium, and dysprosium hexaborides were measured over the temperature range 5-300 K. The temperature dependences and the standard values of the enthalpy, entropy, and the Gibbs energy were calculated by taking into account the nuclear contribution to the heat capacity.
Thermodynamic properties of the rare earth borides and carbides in a wide temperature range
Bolgar, A. S.,Muratov, V. B.,Blinder, A. V.,Kryklya, A. I.,Suodis, A. P.
, p. 127 - 128 (2008/10/08)
For the first time a systematic study was made of the heat capacity and enthalpy of the rare earth tetra- and hexaborides and sesqui- and dicarbides in the temperature range 60-2300 K.
SYNTHESIS OF CERIUM AND GADOLINIUM BORIDES USING BORON CAGE COMPOUNDS AS A BORON SOURCE.
Itoh, H.,Tsuzuki, Y.,Yogo, T.,Naka, S.
, p. 1259 - 1266 (2008/10/08)
Cerium borides (CeB//4 and CeB//6) and gadolinium borides (GdB//4 and GdB//6) were synthesized using boron cage compounds M//2(B//1//0H//1//0)//3 (M equals Ce and Gd) as a boron source. A mixture of hexaboride (CeB//6 or GdB//6) and amorphous boron was formed by thermal decomposition above 1000 degree C or 1200 degree C, respectively. These borides contained a small amount of inclusions (oxides, borates, etc. ) which can be removed by acid treatment in HCl solution with the formation of single phases.
