Structural, Magnetic, Magnetocaloric and Mössbauer Spectrometry Study of $${\hbox {Gd}}_2{\hbox {Fe}}_{17-x}{\hbox {Cu}}_x$$ ($$x=$$x= 0, 0.5, 1 and 1.5) Compounds

The structure, magnetic and magnetocaloric properties of arc-melted \({\hbox {Gd}}_2{\hbox {Fe}}_{17-x}{\hbox {Cu}}_x\) (\(x =\) 0, 0.5, 1 and 1.5) solid solution have been studied. The Rietveld refinement shows that these compounds crystallize in the rhombohedral \({\hbox {Th}}_2{\hbox {Zn}}_{17}\)-type structure with the \(R{\bar{3}}m\) space group, and the substitution of iron by copper leads to a decrease in the unit cell volume. The Curie temperature (\(T_{\mathrm{C}}\)) of the prepared samples depends on the copper content. The reduction of the ferromagnetic phase transition temperature from 475 K (for \(x = 0\)) to 460 K (for \(x = 1.5\)) is due to the substitution of the magnetic element (Fe) by non-magnetic atoms (Cu). The magnetocaloric effect was determined in the vicinity of the Curie temperature \(T_{\mathrm{C}}\). By increasing the Cu content, an increase in the values of magnetic entropy (\(\Delta S_{\mathrm{M}}\)) in a low applied field is observed. The preferred inequivalent crystallographic site of Cu atoms was determined by Mossbauer spectrometry analysis based on the isomer shift parameter correlation with the Wigner–Seitz cell volumes.