A MAGNETIZATION STUDY OF THE FRUSTRATED SPINEL COMPOUND MG1.55FE0.9TI0.55O4

Former studies suggested a reentrant spin-glass-like behavior for the diluted spinel compound Mg1.55Fe0.9Ti0.55O4. Near equilibrium magnetiz ation measurements in very low magnetic fields show, however, that the re is no transition of any kind at any temperature. We suggest that th e long-range ferrimagnetic order is destroyed by the dipolar interacti ons since a moderate magnetic held restores a ferrimagnetic critical b ehavior at 164 K. There is no evidence of a sharp spin glass or cantin g transition at low temperature. Short-range correlations are observed up to 300 K with a slow dynamics. High fields magnetizatization measu rements confirm the reentrant character and give evidence of the froze n disorder or fluctuations which give rise to strong high field suscep tibility.