Magnetic properties and possibility of spontaneous spin-reorientation in the Fe-sublattice of intermetallic compounds Tm(Fe 1− xRh x) 2

A series of quasiternary intermetallic compounds Tm(Fe x Rh 1− x ) 2 with x=0–1 were synthesized and X-ray investigations of crystalline structure were conducted. In the composition range close to x=0.5 a new ordered cubic C1 b-phase was detected. The measurements of Mössbauer spectra as well as the temperature dependence of magnetization and susceptibility were performed. On the concentration dependence of mean magnetic moment per molecule, a strong maximum was observed at the equiatomic composition TmFeRh that may be caused by the antiferromagnetic compensation of Fe–Rh sublattice in the ferrimagnetic compound. In the temperature dependence of magnetic susceptibility of all compounds except for x=0 and 1 we have detected anomalies at ∼3 K evidently due to spin-reorientation at these temperatures. The measurements of Mössbauer spectra proved the existence of C1 b-phase and permitted to determine the local magnetic moments of Fe-ions in it which exceeded significantly the values for C15-phase.