Heterogeneous magnetic state in hydrogen-amorphized GdFe2

Mushnikov, N. V.; Goto, T.; Zajkov, N.K.; Гавико, В. С.; Serikov, V. V.; Kleinerman, N. M.; Yermakov, A. Ye.

doi:10.1016/s0925-8388(98)00964-5

Cited by 10 publications

(8 citation statements)

References 12 publications

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“…If we accept the free-ion value µ Gd = 7 B and the value of µ Co = 1.1 B /Co characteristic of am-YCo 2 H x , the composition of the collinear ferrimagnetic amorphous phase for hydrogenamorphized am-GdCo 2 H x will correspond to GdCo 2.4 H x . A similar composition of the amorphous phase was determined for am-GdFe 2 H x hydrides using magnetization and Mössbauer data [16]. However, the only magnetization data available for am-GdCo 2 H x allow us to determine the stoichiometry of the amorphous phase with a relatively large uncertainty due to an uncertainty in the determination of ferrimagnetic saturation moment.…”

Section: Resultsmentioning

confidence: 70%

“…This value is slightly larger than 1.1 B /Co in am-YCo 2 H x . As it was shown for hydrogen-amorphized GdFe 2 [16], the amorphous state can be expected to be non-uniform. The main amorphous phase is likely enriched in Co relative to the RCo 2 stoichiometry, while the remaining R formed a RH 2 -type phase, traces of which are usually observed by X-ray diffraction (see Fig.…”

Section: Resultsmentioning

confidence: 86%

“…However, if the metallic atoms can move over a long distance, the amorphous phase decomposes into RH 2 (RH 3 ) and Co. Therefore, the short-range order in the amorphous phase is likely to depend on the temperature and time of hydrogen treatment [9,16].…”

Section: Resultsmentioning

confidence: 99%

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Magnetic properties of hydrogen-amorphized RCo2Hx (R=Gd, Tb, Dy, Ho, Er, Tm and Y) alloys

Mushnikov

Гавико

Goto

2005

Journal of Alloys and Compounds

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Section: Resultsmentioning

confidence: 70%

Section: Resultsmentioning

confidence: 86%

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Magnetic properties of hydrogen-amorphized RCo2Hx (R=Gd, Tb, Dy, Ho, Er, Tm and Y) alloys

Mushnikov

Гавико

Goto

2005

Journal of Alloys and Compounds

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“…[1][2][3][4][5][6][7][8] Although the effect of hydrogenation on magnetic properties of C15 Laves phases RFe 2 has been extensively investigated by many groups, [9][10][11] the conditions and the mechanism of HIA in RFe 2 are still unclear. Recently, the present authors clarified origins of thermal peaks of C15 Laves phases RFe 2 during heating in 1.0 MPa H 2 .…”

Section: Introductionmentioning

confidence: 99%

Pressure Dependence of Hydrogen-Induced Amorphization in C15 Laves Phase TbFe<SUB>2</SUB>

et al. 2002

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The pressure dependence of structural changes of C15 Laves phase TbFe 2 heated in a hydrogen atmosphere was investigated using a pressure differential scanning calorimeter (PDSC), a powder X-ray diffractometer (XRD), a differential scanning calorimeter (DSC) and a hydrogen analyzer. Hydrogen absorption in the crystalline state, hydrogen-induced amorphization (HIA), precipitation of TbH 2 and decomposition of the remaining amorphous alloy into α-Fe and TbH 2 occurred exothermally with increasing temperature above 0.5 MPa H 2 , independent of the heating rate. HIA and precipitation of TbH 2 occurred simultaneously in 0.2 MPa H 2 (0.33 K/s) and in 0.1 MPa H 2 (0.17 K/s). On the contrary, hydrogen absorbed crystalline c-TbFe 2 H 3.5 decomposed directly into α-Fe and TbH 2 in 0.1 MPa H 2 (0.33 K/s). That is, no amorphous phase was formed at the lower hydrogen pressure and at a high heating rate. The reason why HIA occurs above the critical hydrogen pressure and below the critical heating rate was discussed on the basis of the hydrogen content absorbed in the crystalline state of TbFe 2 .

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“…[1][2][3][4][5][6][7][8] Among these amorphizing compounds, HIA of C15 Laves phases RM 2 (R = rare earth metal, M = Fe, Co, Ni) is particularly interesting, because they contain industrially important magnetic elements, and both crystalline and amorphous hydrides are formed depending on the hydrogenation temperature. Although the effect of hydrogen absorption on magnetic properties of C15 Laves phases RFe 2 has been extensively investigated by many groups, [9][10][11] conditions and the mechanism of HIA in RFe 2 are still unclear. Recently, Aoki et al have clarified the origins of thermal peaks of C15 Laves phases RFe 2 during heating in 1.0 MPa H 2 .…”

Section: Introductionmentioning

confidence: 99%

Pressure Dependence of Hydrogen-Induced Amorphization in C15 Laves Phases TbM<SUB>2</SUB> (M=Fe, Co and Ni)

2002

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The hydrogen pressure dependence of structural changes in C15 Laves phases TbM 2 (M = Fe, Co and Ni) were investigated between 0.1 and 5.0 MPa H 2 in order to elucidate conditions and the mechanism of hydrogen induced amorphization (HIA). General thermal reactions occur on heating as follows; hydrogen absorption in the crystalline state, hydrogen-induced amorphization (HIA), precipitation of TbH 2 (or TbNi 5 H x ) and decomposition of the remaining amorphous alloys. Exceptionally, a single-phase amorphous a-TbFe 2 H x was not formed below 0.2 MPa H 2 in TbFe 2 , because HIA and precipitation of TbH 2 simultaneously occurred. On the other hand, a single-phase a-TbNi 2 H x was not formed below 1.0 MPa H 2 because of the low hydrogen contents in c-TbNi 2 H x . The present work indicates that hydrogen absorption more than 1.0 (H/M) is essential for the occurrence of HIA in the C15 Laves phases TbM 2 .

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Heterogeneous magnetic state in hydrogen-amorphized GdFe2

Cited by 10 publications

References 12 publications

Magnetic properties of hydrogen-amorphized RCo2Hx (R=Gd, Tb, Dy, Ho, Er, Tm and Y) alloys

Magnetic properties of hydrogen-amorphized RCo2Hx (R=Gd, Tb, Dy, Ho, Er, Tm and Y) alloys

Pressure Dependence of Hydrogen-Induced Amorphization in C15 Laves Phase TbFe<SUB>2</SUB>

Pressure Dependence of Hydrogen-Induced Amorphization in C15 Laves Phases TbM<SUB>2</SUB> (M=Fe, Co and Ni)

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