A systematic study of structural, magnetic and electrical properties of (La1-xTbx)2/3Ca1/3MnO3 perovskites

A thorough study of the (La1-xTbx)2/3Ca1/3MnO3 series has been carried out. All of the samples have the same orthorhombic crystallographic structure. However, the magnetic, magnetoelastic and electrical properties show drastic changes with the Tb content. The decrease in the intensity of the ferromagnetic double-exchange interaction has been correlated with the increase in the Tb content and the decrease in the Mn-O-Mn bond angle, which leads to a decrease in the electron transfer between Mn 3d and O 2p orbitals. Two magnetic phases have been detected at low temperatures: an insulator spin-glass phase in samples with high Tb contents and a metallic ferromagnetic phase in samples with low Tb contents. (author)