MAGNETIC PROPERTY AND PHASE-DIAGRAM OF A FRUSTRATED SYSTEM WITH COMPETING EXCHANGE INTERACTIONS, FEXMN1-XTIO3

Systematic studies of a random mixture FexMn1-xTiO3 with competing exchange interactions have been made by low-field dc-magnetization measurements. Typical behavior characterizing a spin-glass transition is observed in the samples with intermediate Fe concentrations. The samples with Fe- and Mn-rich concentrations undergo the transition to the antiferromagnetic phase, and the samples with certain concentrations reenter into the reentrant spin-glass phase at low temperatures. From these results, the concentration versus temperature phase diagram is determined. In FexMn1-xTiO3 the characteristic properties of the spin-glass and reentrant spin-glass appear strongly, that is because FexMn1-xTiO3 is a magnetically condensed system with strong frustration. The magnetic properties observed in the antiferromagnetic phase of this system have clarified that the spin configuration is quite different from those in ordinary antiferromagnets.