Showing papers on "Erbium published in 1968"

Absorption Spectra of Erbium Tricyclopentadienide at Liquid‐Helium Temperature

Abstract: The absorption spectra of Er(C5H5)3 in 2‐methyl tetrahydrofuran have been studied at room temperature, liquid‐nitrogen, and liquid‐helium temperature. Hypersensitive line groups have been found at ∼19 000 and ∼26 000 cm−1. Large splittings of J = 32 levels have also been observed. A correlation between hypersensitivity and large second‐degree terms of the crystalline potential is suggested. Although some line groups in Er(C5H5)3 showed unusually large splittings, no drastic changes in the usual energy‐level pattern for 4f11 were found in this volatile, organometallic compound of erbium.

Hemispherical Spectral Emittance of Selected Rare Earth Oxides

Abstract: The hemispherical spectral emittances for the sesquioxides of yttrium, samarium, gadolinium, erbium, thulium, and ytterbium are given for five wavelengths in the visible portion of the spectrum over the range of 1400° to 3000°K. A reflectance technique incorporating a carbon arc image furnace and a standard of reflectance was used in the determinations. The emittance of zirconium dioxide was measured to check the validity of the method.

Laser material comprised of erbium and ytterbium doped glass core and neodymium doped glass sensitizer element

Abstract: A LASER MATERIAL CONSISTING OF A GLASS ROD COMPOSED OF TWO DIFFERNETLY DOPED GLASSES, ONE GLASS COMPRISES A LASERABLE CORE AND A SECOND GLASS COMPRISES A SENSITIZER ELEMENT. THE GLASS WHICH COMPRISES A LASERABLE CORE CONTAINS ERBUIM AS THE LASERABLE ION AND ALSO INCLUDES YTTERBIUM OXIDE AS A SENSITIZER. THE GLASS WHICH COMPRISES THE SENSITIZER ELEMENT CONTAINS NEODYMIUM OXIDE AND YTTERBIUM OXIDE WHICH ACT SOLEY AS SENSITIZER IONS. WHEN THE GLASS ROD IS PUMPED WITH OPTICAL ENERGY, A LARGE AMOUNT OF ENERGY IS ABSORBED BY THE NEODYMIUM AND YTTERBIUM IONS N THE SENSITIZER ELEMENT, WHICH ENERGY IS TRANSMITTED INTO THE LASERABLE CORE BY BOTH RADIATIVE AND NON-RADIATIVE PROCESSES TO ASSIST IN PRODUCING A STATE OF POPULATION INVERSION IN THE ERBIUM IONS PRESENT WITHIN THE CORE.

Mechanical properties of polycrystalline erbium from 77 ° to 750 °K☆

Abstract: The flow-stress temperature dependence, strain-rate sensitivity, strain-hardening exponent, and ductility of erbium were determined from 77 ° to 750 °K at strain rates of 0.002, 0.01, 0.1 and 1.0 min−1. The results are presented and comparisons of the properties of erbium with those of other low- c a h.c.p. metals are discussed.

The influence of erbium doping on the velocity of magnetic domain-wall propagation in yttrium iron garnet

Abstract: We discuss the additional damping to which magnetic domain wall motion is subject due to the replacement of a small proportion of the yttrium in yttrium iron garnet by erbium. Published ferromagnetic resonance data for a specimen of composition Er0078Y2922Fe5O12 are used to predict the wall mobility in this material assuming that the erbium doping, acting according to the longitudinal relaxation model, is the sole cause of damping. Measurements are reported of the time taken to reverse the flux in single crystal toroids of pure yttrium iron garnet and of the above composition when reversal takes place by domain wall motion, following the sudden application of a magnetic field. Comparison of theory and experiment shows that the proposed mechanism controls the reversal time for the doped material between 3 °K and 60 °K, where the predicted damping is strong. At higher and lower temperatures the controlling mechanism, which appears to be the same in the doped and pure samples, is different and not understood.

An estimate of the atmospheric propagation characteristics of 1.54 micron laser energy

Abstract: : Potential atmospheric effects on the propagation of electromagnetic radiation at 1.54 micron wavelength are examined. The results of transmission measurements by various investigators, as reported in the literature, coupled with theoretical calculations are applied to estimate the transmission characteristics for erbium ion (Er(+++)) laser radiation in this region. The output of the Er(+++) laser at 1.54 microns is discussed in some detail. Predominant attenuation mechanisms are found to be aerosol absorption and aerosol scattering. Contributions from five investigations of atmospheric transmission in this region are summarized. Nonlinear effects are not considered.

The magnetic properties of single crystals of erbium and some yttrium-erbium and lutetium-erbium alloys between 1.2 and 300°K

Abstract: Carefully analyzed splierical cinclc crystal riamplex wore prepared oL' orbiiiiu and of alloyy whose approximate compositions were: , Y^oEr,;^. Y?Er-^ , LUo-jEr^^, Lu^oEr^o, and . Ma^pietie measureraerits were made on each ol' these samples along the tt'iroc principle crystallographic axes in the range 1.2 to gOO^K and applied fields up to K-Oe. For pure erhiim, the saturation moment along the c-axis was found to be 270.O ±2.0 emu/g. by fitting the data to a plot and extrapolating to 0°K. This is to be compared with a theoretical value of 3OO.5 emu/g. The discrepancy between experiment and theory is apparently the result of a ferromagnetic spiral arrangement of spins where the spins are cocked at an angle to the c-axis rather than being aligned parallel to it. Curie and N^el temperatures were found at l8.2 ±0.5 and 86.5 ±0.5°K respectively. Peaks in the c-axis moment vs. temperature curves were also observed which extrapolated to zero-field temperatures of 28.0 ±0.5 and 50.5 ±0.5°K. The latter corresponds to the transition from one antiferromagnetic structure to another while the significance of the former is unknown. Peaks occurred in both the aand b-axis moment vs. temperature curves below about 18.5 K-Oe. Below about 10 X-Oe., the temperature of the peaks was field independent and occurred at about l8.2°K. In both the aand b-axis moment vs. field curves, there were discontinuous increases in moment at about 18.5 K-Oeo near 4.2°K. These apparently correspond to a sudden transition to a nearly parallel alignment of spins at an angle of about 23° to the c-axis. Some very small basal-plane anisotropy was observed below 40°K. At 4.2°X, the b-axis moment was about 2% larger at .high