Crystal structure and magnetic properties of R5Sn4 alloys, where R is Tb, Dy, Ho, and Er

Crystal structure and magnetic properties of R5Sn4 alloys with R = Tb, Dy, Ho, and Er have been studied. R5Sn4, R11Sn10, and R5Sn3 phases coexist in the annealed alloys and the content of 11:10 and 5:3 phases varies between 9 and 17 wt.%. The R5Sn4 major phase has Sm5Ge4-type orthorhombic structure with space group Pnma. Tb5Sn4 has a complex magnetic structure, spin re-orientation and ferrimagnetic-paramagnetic phase transitions occur at similar to 54 and similar to 84 K, respectively. For Dy5Sn4, Ho5Sn4, and Er5Sn4, the antiferromagnetic-paramagnetic phase transitions occur at about 22, 15, and 8 K, respectively. The magnetic entropy changes (-Delta S-M) of all alloys are negative at low temperature and changes to positive at higher temperatures, which could be attributed to the change of magnetic states. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3549562]