Low temperature magnetism in the rare-earth perovskite GdScO3

2020 ◽  
Vol 29 (5) ◽  
pp. 057503
Author(s):  
Jie-Ming Sheng ◽  
Xu-Cai Kan ◽  
Han Ge ◽  
Pei-Qian Yuan ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
The Rare Earth

scholarly journals EFFECTS OF THE LOW TEMPERATURE SEA-FLOOR WEATHERING ON THE RARE EARTH ELEMENTS OF THOLEIITIC BASALTS

1979 ◽  
Vol 18 (4) ◽  
pp. 385-394
Author(s):  
J. Urrutia Fucugauchi
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
Baja California ◽  
Sea Floor ◽  
The Rare Earth

El presente trabajo se basa en resultados de elementos de tierras raras obtenidas en basaltos toleíticos provenientes de la boca del Golfo de California, México. Los basaltos fueron muestreados durante una operación de dragado en la latitud de 23° N.Los elementos de tierras raras fueron obtenidos por el método instrumental de activación por neutrones (López et al.. 1978). Las muestras fueron tomadas entre la cresta de la Dorsal de Pacífico Este y la plataforma continental de la península de Baja California. Las edades asignadas a las muestras con base en datos de anomalías magnéticas y de la relación batimetría edad del fondo oceánico son de 0, 1.7 y 3.5 millones de años. Los datos son empleados en este trabajo para evaluar el comportamiento de las tierras raras durante procesos de alteración a bajas temperaturas. Fue usado un procedimiento de normalización propuesto por Ludden y Thompson (1978) para datos de basaltos en la dorsal del Atlántico Medio (23°N). No obstante que el valor de la normalización (esto es, la abundancia de Yb para basaltos sin alteración) puede no ser válido para los basaltos de la Dorsal de Pacífico Este (23°N), los resultados obtenidos son consistentes y reflejan los efectos de alteración. Dichos resultados están de acuerdo con el modelo propuesto por Ludden y Thompson. Las muestras reflejan un enriquecimiento progresivo de las tierras raras ligeras (La a Sm) con la alteración (edad). Por otro lado, las diferencias observadas con respecto a los resultados anteriores indican que las tierras raras no se comportaran se igual forma en todos los ambientes de alteración. En particular, el elemento Ce muestra anomalías positivas y negativas. El agua de mar tiene una anomalía negativa, de aquí que este comportamiento puede ser interpretado en términos de la abundancia de Ce en el agua de mar o bien su fraccionamiento del agua de mar.

scholarly journals Low-temperature magnetostriction and distortions in the rare-earth Laves phases

2019 ◽  
Vol 1389 ◽  
pp. 012097
Author(s):  
G Politova ◽  
M Ganin ◽  
T Kaminskaya ◽  
A Mikhailova ◽  
B Nacke ◽  
...  
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Laves Phases ◽  
The Rare Earth

Low‐Temperature Thermoelectric Power of the Rare‐Earth Metals

1961 ◽  
Vol 32 (12) ◽  
pp. 2543-2549 ◽  
Author(s):  
H. J. Born ◽  
Sam Legvold ◽  
F. H. Spedding
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Thermoelectric Power ◽  
Rare Earth Metals ◽  
The Rare Earth

Influence of Sintering Temperature on the Thermoluminescence Spectra of MgSO4 Doped with RE(Tm,Dy) and Mn

2014 ◽  
Vol 664 ◽  
pp. 57-61
Author(s):  
Jing Yuan Guo ◽  
Qiang Tang ◽  
Li Gao ◽  
Ting Ting Lan ◽  
Chun Xiang Zhang ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Complex Structure ◽  
Rare Earth Ions ◽  
3 Dimensional ◽  
Luminescence Process ◽  
Co Doped ◽  
The Rare Earth

In this paper, MgSO4:Dy,MgSO4:Tm and MgSO4:Mn phosphors are prepare by high temperature solid state reaction. The MgSO4:Dy or MgSO4:Tm powder are mixed and sintered with MgSO4:Mn respectively to obtain the co-doped MgSO4:Dy,Mn and MgSO4:Tm,Mn phosphors. The 3-dimensional thermoluminescence spectra of these two phosphors under different sintering temperature are measured.Results show that when the sintering temperature is below 800°C, Dy, Tm and Mn ions emissions are independent. However, when the sintering temperature was over 800°C, the emission peak of Mn becomes weaker, and so do the low temperature peaks of Dy and Tm, while the high temperature peaks of Dy and Tm become stronger. This indicated that the defect complex structure in the formation of the thermoluminescence material depends on the sintering temperature. As the sintering temperature rises, more and more Mn ions combine with the rare earth ions. Therefore, the luminescence process of the energy transfer of Mn ions to the rare earth ions can be observed and the suppression to low temperature peaks of Tm and Dy, and also shown in spectra.

Low-temperature phase transitions in the rare-earth ferroborate Nd0.75Dy0.25Fe3(BO3)4

2010 ◽  
Vol 36 (3) ◽  
pp. 279-281 ◽  
Author(s):  
G. A. Zvyagina ◽  
K. R. Zhekov ◽  
I. V. Bilych ◽  
A. A. Zvyagin ◽  
L. N. Bezmaternyhk ◽  
...  
Keyword(s):  
Rare Earth ◽  
Phase Transitions ◽  
Low Temperature ◽  
Temperature Phase ◽  
Low Temperature Phase ◽  
The Rare Earth

MAGNETIC PROPERTIES OF R2In (R=Gd, Tb, Er)

1993 ◽  
Vol 07 (01n03) ◽  
pp. 818-821 ◽  
Author(s):  
D. RAVOT ◽  
O. GOROCHOV ◽  
T. ROISNEL ◽  
G. ANDRE ◽  
F. BOUREE-VIGNERON ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Low Temperature ◽  
Neutron Diffraction ◽  
Antiferromagnetic State ◽  
Powder Neutron Diffraction ◽  
Magnetic Transport ◽  
The Rare Earth

For all the Rare-Earth (R) the R2In form in the same crystal structure (P63/mmc). These compounds show a great variety of magnetic behaviors. When the temperature decreases, the magnetic susceptibility of Er2InTb2In and Gd2In increases, passes through a maximum then decreases. For Gd2In this behavior was associated with change from a paramagnetic to a ferromagnetic then to an antiferromagnetic state. We have performed magnetic, transport (Tb, Er), Mössbauer spectroscopy (Er) and powder neutron diffraction experiments (Gd, Tb, Er) on these compounds. Unlike Gd2In the resistivity of Tb2In and Er2In does not reveal any anomaly at the temperature where the susceptibility begins to decrease and the Tb2In and Er2In magnetizations show the same behavior at all temperatures in the ordered region. Neutron diffraction experiments reveal ferromagnetic and antiferromagnetic structures at low temperature.

Die Selten-Erd-Metall(III)-Fluorid-Oxoselenate(IV) MF[SeO3] (M = Y, Ho–Lu) imYF[SeO3]-Typ/ The Rare-Earth Metal(III) Fluoride Oxoselenates(IV) MF[SeO3] (M = Y, Ho–Lu) with YF[SeO3]-type Structure

2009 ◽  
Vol 64 (4) ◽  
pp. 375-382 ◽  
Author(s):  
Christian Lipp ◽  
Thomas Schleid
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Metal ◽  
Room Temperature ◽  
Earth Metal ◽  
Selenium Dioxide ◽  
Molar Ratios ◽  
Triclinic Structure ◽  
Fluxing Agent ◽  
The Rare Earth

YF[SeO3]-type rare-earth metal(III) fluoride oxoselenates(IV) MF[SeO3] (M = Y, Ho-Lu) crystallize monoclinically in space group P21/c (no. 14) with Z = 4. Obeying the lanthanoid contraction, the lattice parameters decrease successively from a = 657.65(7), b = 689.71(7), c = 717.28(7) pm and β = 99.036(5)° for YF[SeO3] at 298 K to a = 648.39(6), b = 681.28(7), c = 705.81(7) pm and β = 98.657(5)° for LuF[SeO3] at 100 K (LT-LuF[SeO3], LT ≡ Low Temperature). The M3+ cations are occupying the general site 4e. Contrary to the triclinic structure of RT-LuF[SeO3] (RT ≡ Room Temperature; CN(Lu3+) = 7) the higher coordination number eight is achieved for the M3+ cations in all YF[SeO3]-type compounds. This results in [MO6F2]11− polyhedra (d(M-O) = 228 - 243/225 - 239 plus 263/258 pm, d(M-F) = 219/216 pm, M = Y/Lu), which are connected via common O・ ・ ・O edges to form infinite chains 1∞{[MOe 4/2Ot 2/1Ft 2/1]7−} (e ≡ edge-sharing, t ≡ terminal) running along [010]. Neighboring chains share common O3・ ・ ・O3 and O3・ ・ ・F edges generating 2∞{[M(O3)3/3(O2)2/2(O1)1/1F2/2]4−} sheets parallel to the (100) plane. Finally, these 2 ∞{[MO3F]4−} sheets are interconnected by Se4+ cations, which appear in isolated ψ1-tetrahedral [SeO3]2− anions (d(Se-O) = 167 - 175 pm). For the synthesis of the YF[SeO3]-type rare-earth metal(III) fluoride oxoselenates( IV) MF[SeO3] (M = Y, Ho-Lu), the rare-earth metal sesquioxides (M2O3) and trifluorides (MF3), and selenium dioxide (SeO2) in molar ratios of 1 : 1 : 3 with the fluxing agent CsBr were reacted within five days at 700 - 750 °C in evacuated graphitized silica ampoules.

scholarly journals CO2 Methanation over Rare Earth Doped Ni-Based Mesoporous Ce0.8Zr0.2O2 with Enhanced Low-Temperature Activity

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 463
Author(s):  
Zhenglong Yang ◽  
Yan Cui ◽  
Pengxiang Ge ◽  
Mindong Chen ◽  
Leilei Xu
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
Low Temperature ◽  
Impregnation Method ◽  
Co2 Methanation ◽  
X Ray ◽  
Wide Range ◽  
Temperature Programmed ◽  
Rare Earth Doped ◽  
The Rare Earth

The Ni-based catalysts have a wide range of industrial applications due to its low cost, but its activity of CO2 methanation is not comparable to that of precious metal catalysts. In order to solve this problem, Ni-based mesoporous Ce0.8Zr0.2O2 solid solution catalysts doped with rare earth were prepared by the incipient impregnation method and directly used as catalysts for the methanation of CO2. The catalysts were characterized systematically by x-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, x-ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (H2-TPR), CO2 temperature programmed desorption (CO2-TPD), and so on. The results show that Ni is highly dispersed in the mesoporous skeleton, forming a strong metal–skeleton interaction. Therefore, under the condition of CO2 methanation, the hot sintering of metallic Ni nanoparticles can be effectively inhibited so that these mesoporous catalysts have good stability without obvious deactivation. The rare earth doping can significantly increase the surface alkalinity of catalyst and enhance the chemisorption of CO2. In addition, the rare earth elements also act as electron modifiers to help activate CO2 molecules. Therefore, the rare earth doped Ni-based mesoporous Ce0.8Zr0.2O2 solid solution catalysts are expected to be an efficient catalyst for the methanation of CO2 at low-temperature.

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