Structure and magnetic properties of ErFe11-xGaxTi

ErFe11-xGaxTi compounds with ThMn12-type structure were synthesized for x = 0, 1, 2, 3, 4, 5. The crystalline structure and Ga occupancy in the compou nds were analysed in terms of the Rietveld method. With increasing Ga conte nt, the lattice constant and unit-cell volume increase monotonically. Ti at oms are found to occupy 8i sites for all the compounds. Bond length and Ga occupancy factor are given. The Curie temperature increases first, going th rough a maximum and then decreases with increasing x while saturation magne tization decreases monotonically. Spin re-orientation from the uniaxial to the easy-cone type is detected for all the compounds as the temperature dec reases from 300 to 5 K. A tentative spin phase diagram is constructed for t he ErFe11-xGaxTi. In the ErFe11-xGaxTi compounds, a magneto-history effect is observed which can be attributed to irreversible movement of narrow doma in walls that are easily pinned.