Magnetic Properties of Sm1-xTbxNi4B compounds

Physical properties of the Sm1-x Tb (x) Ni4B (0a parts per thousand currency signxa parts per thousand currency sign0.8) compounds have been investigated by means of the X-ray powder diffraction, AC-susceptibility and DC-magnetization techniques. All the compounds studied crystallize in CeCo4B-type structure with P6/mmm space group. The substitution of Tb for Sm leads to a decrease of the unit-cell parameters a,c and the unit-cell volume V. The magnetic phase transition temperatures are found as 39, 30, 26, 22 and 15 K, for x=0, 0.2, 0.4, 0.6 and 0.8, respectively. In addition, we have seen the second magnetic phase transition around 230 K, at the ac-susceptibility results. We have concluded that this behavior may arise from the Tb-Tb interaction in crystal structure.