Structural and magnetic modifications induced by hydrogen atoms occupying interstitial sites in GdNiInH0.5 compound
| Autor: | Artur W. Carbonari, Jose A. H. Coaquira, José Mestnik-Filho, J. André-Filho, A. L. Lapolli |
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| Rok vydání: | 2012 |
| Předmět: |
Magnetic moment
Hydride Chemistry Mechanical Engineering Metals and Alloys Intermetallic Condensed Matter::Materials Science Paramagnetism Crystallography Ferromagnetism Mechanics of Materials Formula unit Interstitial defect Materials Chemistry Curie temperature Physics::Atomic Physics Atomic physics |
| Zdroj: | Journal of Alloys and Compounds. 545:63-66 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2012.08.042 |
| Popis: | The structural and magnetic properties of GdNiIn intermetallic compound and its hydride have been studied. The GdNiIn compound crystallizes in the ZrNiAl-type structure. The structural study indicates that after hydrogenation the crystal structure remains the same and suggests that hydrogen atoms likely occupy 4 h and 2 d interstitial sites; meanwhile the unit cell expands in ∼2%. The magnetic characterization shows that the presence of hydrogen modifies the magnetic properties of the host compound. Two main effects have been observed: a decrease of the magnetic moment per formula unit and a reduction of the ferromagnetic Curie temperature ( T C ). The decrease of the magnetic moment has been speculatively interpreted as follows. The entrance of hydrogen atoms into the intermetallic lattice induces a magnetic moment in Ni atoms. Therefore, the effective magnetic moment determined for GdNiInH 0.5 comes from Gd and Ni atoms, which magnetic moments are oriented antiparallel to each other. On the other hand, the increase of interatomic distances leads to weakening of the coupling constant of Gd–Gd atoms, resulting in a decrease of T C after the hydrogen absorption. |
| Databáze: | OpenAIRE |
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