Magnetic properties and <sup>155</sup>Gd Mossbauer effect in GdCu<sub>2</sub> and its ternary hydride
H de Graaf; R C Thiel; K H J Buschow; H de Graaf; Kamerlingh Onnes Lab., RA Leiden, Netherlands; R C Thiel; Kamerlingh Onnes Lab., RA Leiden, Netherlands; K H J Buschow; Kamerlingh Onnes Lab., RA Leiden, Netherlands
Журнал:
Journal of Physics F: Metal Physics
Дата:
1982-06-01
Аннотация:
The magnetic and crystallographic properties of GdCu<sub>2</sub> and its ternary hydride GdCu<sub>2</sub>H<sub>x</sub> have been investigated. Upon hydrogen absorption the crystal structure of GdCu<sub>2</sub> changes from orthorhombic (CeCu<sub>2</sub>-type) to tetragonal (MoSi<sub>2</sub>-type), accompanied by a lattice expansion of 29%. The uncharged intermetallic compound GdCu<sub>2</sub> orders antiferromagnetically (T<sub>N</sub>=37K). After H<sub>2</sub> absorption it becomes ferromagnetic (T<sub>C</sub>=45K). There is a strong increase in the asymptotic Curie temperature (from theta <sub>p</sub>=7K to theta <sub>p</sub>=57K). Studies of the <sup>155</sup>Gd Mossbauer effect in the uncharged and charged compounds show that the H<sub>2</sub> absorption leads to an increase in isomer shift and in the absolute value of the hyperfine field at 4.2K. Both changes have been discussed in terms of a changing conduction electron concentration.
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