Magnetic and magnetoelastic properties of amorphous and crystalline TbFe2Hx hydrides

Yermakov, A. Ye.; Mushnikov, N. V.; Zajkov, N.K.; Гавико, В. С.; Barinov, V. A.

doi:10.1080/13642819308217945

Cited by 25 publications

(8 citation statements)

References 5 publications

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“…HIA is closely related to the disproportionation reaction that dominates a lifetime of hydrogen storage alloys, so that it is important to make clear the controlling factors of HIA. HIA has been observed in the intermetallic compounds A x B 1−x consisting of hydride forming (A) and non-hydride forming metals (B) with the crystal structures such as C15, B8 2 , C23, D0 19 and L1 2 [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Among these, structural changes in the C15 Laves phases RFe 2 (R = rare earth metals) are particularly interesting, because both a crystalline and an amorphous hydride form depending on the hydrogenation temperature [12].…”

Section: Introductionmentioning

confidence: 99%

Process and mechanism of hydrogen-induced amorphization in C15 Laves phases RFe2

Aoki

Ishikawa

2005

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 99%

Process and mechanism of hydrogen-induced amorphization in C15 Laves phases RFe2

Aoki

Ishikawa

2005

Journal of Alloys and Compounds

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“…On the other hand, it has been known that intermetallic compounds A x B 1Àx with the C15, B8 2 , C23, D0 19 and L1 2 structures amorphize by hydrogenation, [1][2][3][4][5][6][7][8][9][10][11][12][13][14] which is called hydrogen-induced amorphization (HIA). HIA is a practically important phenomenon, because it is closely related to the disproportional reaction that determines the lifetime of hydrogen storage alloys.…”

Section: Introductionmentioning

confidence: 99%

Pressure Dependence of Hydrogen-Induced Transformations in C15 Laves Phase DyCo2

Ishikawa

Aoki

2004

Mater. Trans.

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Structural changes in C15 Laves phase DyCo 2 heated in a hydrogen atmosphere between 0.1 and 5.0 MPa were investigated using a pressure differential scanning calorimeter (PDSC) and were compared with those of DyFe 2 . Four exothermic reactions resulting from 1) hydrogen absorption forming crystalline and amorphous hydrides, 2) hydrogen-induced amorphization (HIA), 3) the precipitation of BiF 3 -type DyH 3 in the amorphous hydride and 4) the decomposition of the remaining amorphous hydride into DyH 3 + -Co were observed with increasing temperature. HIA in DyCo 2 occurred for every hydrogen pressure in contrast to DyFe 2 , because the pressure dependence of it is small. The mechanism of the phase transformations for DyCo 2 in a hydrogen atmosphere was discussed on the basis of the experimental results such as the pressure dependence of T p and T p =T m (the peak temperature/the melting point of DyCo 2 ), the enthalpy change ÁH, the activation energy E A and so on.

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“…Buschow [1,2] studied the Gd-Fe system and showed that GdFe 2 has a magnetic ordering temperature, T c = 796 K, and a saturation moment of 3.55 μ B /f.u. Other studies [3][4][5][6][7] of the magnetic properties of the RFe 2 H x ferrimagnet, where R = Gd, Ce, Er, and Ho, compounds for x up to 4.2 indicated that hydrogenation causes a sharp decrease in the energy of the Gd-Fe exchange interaction and an increase in the magnetic moment of iron from 1.6 μ B in the initial compound to 2.2 μ B in the amorphous hydride alloy. Absorption of H also causes the cubic structure to expand and affects strongly the strength of the exchange interaction in these compounds.…”

Section: Introductionmentioning

confidence: 97%

Mössbauer studies of GdFe2 − x Hf x alloys

et al. 2008

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GdFe 2−x Hf x alloys, where x = 0, 0.10, 0.15, 0.20, and 0.30, are produced by arc-melting of pure elements. The samples are investigated by x-ray diffraction and Fe 57 Mössbauer spectroscopy at 78 K and 300 K. We find that the alloy system GdFe 2−x Hf x have the single phase cubic Cu 2 Mg type structure in the whole concentration range. Mössbauer spectroscopic results show that all the samples studied are magnetically ordered at 78 K, and at room temperature. The room temperature spectra are fitted with two magnetic components where the direction of magnetization is along the [111] while the spectra at 78 K are fitted with four magnetic subspectra indicating a complex direction of magnetization for all samples under investigation. The average magnetic hyperfine field and the average isomer shift are found to decrease almost linearly with increasing the Hf concentration at 78 K and 300 K due to the replacement of Fe by nonmagnetic Hf.

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Magnetic and magnetoelastic properties of amorphous and crystalline TbFe₂H_x hydrides

Cited by 25 publications

References 5 publications

Process and mechanism of hydrogen-induced amorphization in C15 Laves phases RFe2

Process and mechanism of hydrogen-induced amorphization in C15 Laves phases RFe2

Pressure Dependence of Hydrogen-Induced Transformations in C15 Laves Phase DyCo<SUB>2</SUB>

Mössbauer studies of GdFe2 − x Hf x alloys

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