Magnetic properties and specific heat of RMnO3 (R = Pr, Nd) -: art. no. 064418

The ground-state properties of the perovskites PrMnO3 and NdMnO3 were investigated by magnetization, magnetic ac susceptibility, and specific heat measurements. A strongly anisotropic behavior has been detected for temperatures below the antiferromagnetic phase transition T(N)approximate to100 K. The susceptibility and the weak spontaneous ferromagnetic moment appear to be different in both compounds due to different anisotropic rare-earth contributions. The specific heat shows strong Schottky-type contributions at low temperatures, which for NdMnO3 strongly depend on the magnetic field. A spin reorientation phase transition (spin-flop type) induced by a magnetic field along the b axis was observed in NdMnO3 at Hsimilar to110 kOe and T=5 K. All results can consistently be explained by anisotropic contributions of the rare-earth ions: In PrMnO3 the electronic ground state is determined by a low-lying quasidoublet split by the crystal field (similar to19 K). In NdMnO3 the Kramers doublet is split by the Nd-Mn exchange field (similar to20 K).