Materials Literature
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The magnetic properties of the spinels M1/2In1/2Cr2X4 with M = Cu or Ag and X = S or Se were investigated. In the sulphides the Cr spins order antiferromagnetically at TN = 40 °K for M = Cu and at TN = 17 °K for M = Ag. No spin ordering above 4 °K was observed in Cu1/2In1/2Cr2Se4, while Ag1/2In1/2Cr2Se4 is ferromagnet…
Powder neutron diffraction measurements have been performed on RbCoBr3. The results indicate that at TN = 36 °K, the compound exhibits a transition to an antiferromagnetic phase in which the spins are alternately aligned along c with a (+ + —) configuration for the three spins in the basal plane. This is in contrast t…
The magnetic moment of cobalt(II) fluorosulfate has been measured over the temperature range 312 to 120 °K and the results agree with theory for cobalt(II) in a regular octahedral ligand environment with λ equal to the free-ion value and no reduction in the magnetic moment due to electron delocalization. From its elec…
Expressions are developed for the orientation dependence of the nuclear quadrupole spin-lattice relaxation in crystals. Restrictions imposed by crystal symmetry are tabulated for the thirty-two nonmagnetic point groups. The possibility of distinguishing between different relaxation processes by means of orientation me…
PrCo5 D4-x(x= 0-,l à 0,3) haz been studied by neutron powder diffraction and by magnetization measurements on aligned powder specimens. The σ|| vs T curve shows a maximum at 50 °K. Above 50 °K the field dependence of the magnetization is small, below 50 °K it is large. In accordance with this, the magnetic structure a…
We discuss the magnetic behavior of rare earth systems where the crystal-field-only ground state of the rare earth ion is a singlet. As exchange increases in such a system, magnetic ordering at zero temperature occurs through a polarization instability of the singlet ground state. Such a process leads to a threshold v…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation of 16,16'-bisnorgeranylgeranyl pyrophosphate by farnesyl pyrophosphate synthetaseShuichi Seto, Tokuzo Nishino, and Kyozo OguraCite this: J. Am. Chem. Soc. 1971, 93, 3, 794–795Publication Date (Print):February 1, 1971Publication History Published online1 May 2002Pub…
An extended feasibility study was made of the use of the metalliding process to the application of highly impervious diffusion coatings on inexpensive conductive metals which normally corrode in acid electrolytes. Tantalum and hafnium, which proved highly corrosion resistant in acid media, are expensive for large scal…
The Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange mechanism is examined for its relevance to ferromagnetism in the rare-earth metals. More specifically, the experimental sensitivity of the exchange energy (or Curie temperature) to the interatomic spacing (applied pressure) of the rare earths is examined in terms of th…
The interaction of ammonia gas, at pressures between 10−7 and 10−2 torr, with a polycrystalline tungsten filament, at temperatures between 200 and 700°K, has been investigated by thermal desorption mass spectrometry. Several procedures have been adopted to overcome the problems caused by the persistence of ammonia gas…
The magnetization and the susceptibility of isostructural compounds (6Mn23-structure) of the composition RE6(MnxFe1-x)23(RE = Y, Gd) have been determined from 4 °K to 1 200 °K. The Curie-temperatures Tc of the RE6Mn23 and the RE6Mn23 compounds (RE = Y, Gd) are in the range from 468 °K to 486 °K. In the case ofY6(MnxFe…
Some of the sources of hairiness of cotton yarns and their blends are investigated. The influence of fiber parameters, spinning process, and yarn parameters are discussed. Also, some contradictions found in the literature in connection with certain aspects of the influence of these parameters on hairiness are clarifie…
Techniques for achieving a microwave time resolving capability in a scanning electron microscope using the stroboscopic mode of operation are presented. By pulsing the primary electron beam with traveling wave electrostatic deflection plates, an over-all system bandwidth in excess of 2 GHz is achieved. A method to det…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of Ba7Fe6S14, a trinuclear iron complexHugo Steinfink, I. E. Grey, and Hwei-Kwan HongCite this: Inorg. Chem. 1971, 10, 2, 340–343Publication Date (Print):February 1, 1971Publication History Published online1 May 2002Published inissue 1 February 1971https://…
The lattice thermal expansion of a number of C atoms and graphites has been studied over the temperature range −265 to 2600°C, and is discussed taking account of other diffraction data published recently. It is shown that for the temperature range 0 to 2600°C, the increase in the interlayer spacing for a given tempera…
The reaction between strontium carbonate and iron(III) oxide has been studied in a system open to the atmosphere and in a vacuum. The extent of reaction was calculated from the analysis of the solid products by X-ray diffraction and, in the case of the experiments in vacuum, from the amount of carbon dioxide evolved f…
The dependence of the coercivity, H c, remanence coercivity, H R, and remanence, M R, on particle size has been investigated at various temperatures from 77°K to 297°K. The results show that H c and H R increase as the particle size and temperature decrease. There is strong evidence for the existence of a critical par…
Abstract Mit Neutronenbeugung wurden die Atomparameter von Coiumbit, FeNb 2 O 6 und MnNb 2 O 6 , verfeinert. Tieftemperaturmessungen an FeNb 2 O 6 ergaben magnetische Reflexe hkl mit k 1/2zahlig. Aus den Reflexintensitäten ergab sich eine kollineare magnetische Struktur \documentclass{article}\pagestyle{empty}\begin{d…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGeneralized Relationship for the Surface Tension of Polar FluidsD. I. Hakim, David Steinberg, and L. I. StielCite this: Ind. Eng. Chem. Fundamen. 1971, 10, 1, 174–175Publication Date (Print):February 1, 1971Publication History Published online1 May 2002Published inissue 1 Fe…
Abstract The results of an x‐ray and polarimetric study of a crystalline modification (form I) of isotactic poly‐(S)‐4‐methyl‐1‐hexene are reported and discussed. The x‐ray fiber spectra of this polymer are practically indistinguishable from those of isotactic poly‐(R)‐(S)‐4‐methyl‐1‐hexene. Although the crystal struc…