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Journal ArticleDOI

Hydrogen absorption and its effect on the magnetic properties of rare-earth iron intermetallics

K.H.J. Buschow1
01 Jul 1976-Solid State Communications (Pergamon)-Vol. 19, Iss: 5, pp 421-423
TL;DR: In this paper, the magnetic properties of the hydrides were determined and compared with the original compounds and it was shown that the magnetic moment per Fe atom is much larger in hydride phases.
About: This article is published in Solid State Communications.The article was published on 1976-07-01. It has received 89 citations till now. The article focuses on the topics: Hydride & Intermetallic.
Citations
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Journal ArticleDOI
TL;DR: In this article, a phenomenological model is described to explain the variation of the hydrogen capacity in pseudobinary compounds A(B1−xB′x)2, assuming a local hydrogen capacity that is a function of the number of B′ atoms that surround the Zr atom.
Abstract: The hydrogen sorption and physical properties of Laves phase AB2 intermetallic compounds are reviewed. The work contains a list of AB2 compounds and their hydrogen capacities. The preferred location of hydrogen in different tetrahedral interstitial sites is calculated assuming the formation of “binary hydrides” between the hydrogen and the four atoms that form the tetrahedral site. A phenomenological model is described to explain the variation of the hydrogen capacity in pseudobinary compounds A(B1−xB′x)2. The model assumes a local hydrogen capacity that is a function of the number of B′ atoms that surround the Zr atom; it is described by a double-step function. The influence of hydrogen on the magnetic properties of the compounds is discussed.

86 citations

Journal ArticleDOI
Abstract: Rare‐earth transition metal compounds are known to be able to (reversibly) absorb large quantities of hydrogen gas at moderate pressures. This absorption of H2 gas leads to substantial changes of the magnetic properties. These include hydrogen induced transitions from Pauli paramagnetism to ferromagnetism. Examples also exist of the reverse effect, i.e., where in ferromagnetic compounds the 3d moment disappears upon hydrogen absorption. The changes in magnetic properties, together with experimental results of X‐ray diffraction and Mossbauer‐effect spectroscopy are discussed in terms of charge transfer and changes in interatomic distances. The metastable character of the ternary hydrides often leads to a loss of the long range atomic order upon hydrogen absorption. This affects not only the absorption capacity (after repeated cycling) but also influences the magnetic behavior. Examples are shown where the atomic disorder has led to pronounced thermomagnetic history effects.

81 citations

Book ChapterDOI
K.H.J. Buschow1
TL;DR: The number of stable binary intermetallic compounds in which one of the components is a rare earth element is of the order of a thousand as discussed by the authors, which encompasses a much larger number of possible atomic arrangements of sufficiently high space filling than would be the case for two components of almost equal size.
Abstract: Publisher Summary This chapter discusses rare earth compounds. The number of stable binary intermetallic compounds in which one of the components is a rare earth element is of the order of a thousand. Combination with elements of much smaller metallic radii then encompasses a much larger number of possible atomic arrangements of sufficiently high space filling than would be the case for two components of almost equal size. A meaningful study of the physical properties of intermetallic compounds can only be made on single phase materials. Only a fraction of the compounds is in single phase condition after the melting together of the components. The chapter explains the compounds with non-magnetic elements and compounds with d-transition metals. It also explains ternary compounds or hydrides.

80 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental basis for interpretation of so-called multiplet splittings in the Fe 3s core-level X-ray photoelectron spectroscopy (XPS) peaks is presented.
Abstract: We present an attempt to establish an experimental basis for interpretation of so-called multiplet splittings in the Fe 3s core-level x-ray photoelectron spectroscopy (XPS) peaks. Fe 3s XPS splittings have been studied in various crystalline and amorphous alloys using x-ray photoelectron spectroscopy. It is found that there is poor correlation between the Fe 3s splitting and the magnetic moment on the Fe atoms in both alloys and inorganic compounds. We even find an Fe 3s splitting in some Pauli paramagnets. The ratio of the satellite to main peak intensity is always less than expected for either the atomic limit, or for itinerant magnetism. The implications of these observations are discussed. It is concluded that the Fe 3s splitting is not a reliable guide to local moments of Fe.

79 citations

Journal ArticleDOI
TL;DR: In this paper, the structural changes of the CeFe2 Laves phase compound during the hydrogen absorption and desorption process have been investigated by X-ray diffraction, transmission electron microscopy, thermal analysis and magnetic property measurements.

74 citations

References
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Journal ArticleDOI
M. Brouha1, K.H.J. Buschow1, A. Miedema1
TL;DR: In this article, the volume dependence of the Curie temperature, the compressibility, and the thermal expansion of several representative members of the group of R -Co and R -Fe intermetallics (R stands for rare earth elements Y, Th, and in one case Zr) has been studied.
Abstract: The pressure derivative of the Curie temperature, the compressibility, and the thermal expansion of several representative members of the group of R -Co and R -Fe intermetallics ( R stands for rare-earth elements Y, Th, and in one case Zr) has been studied. The results derived for the volume dependence of T c agree rather well with the relation ( d \ln T_{c})/(d \ln V) = a+b/T_{c}^{2} in which, for both series of compounds (Co and Fe), the constant a equals about -5/3. This result favors an interpretation of the magnetic properties of these compounds in terms of the collective electron model rather than one in terms of localized moments. For some compounds the thermal expansion above room temperature has been studied. A considerable reduction of the thermal expansion has been observed near T c for those compounds for which dT_{c}/dp is large and negative (invar effect).

101 citations

Journal ArticleDOI
TL;DR: In this paper, the lattice constants at room temperature and the magnetic properties of several members of the series Gd χ La 1- χ Mg were studied in the temperature range 4.2-300 K with applied fields up to 340 kG.

22 citations