Observation of magnetic behavior at low temperature in the Mg2Al4Si5O18 system

The Mg2Al4Si5O18 materials were prepared by the melt-quenching technique using an arc-melter system. The heat treatments of the samples were performed at 1300 °C for 48 h and 72 h. From XRD analysis, while major phase in the samples was the α-cordierite, the MgAl2O4 (spinel) and MgO phases were also detected. It was observed that the uniformly distributed rods are formed perpendicular to the sample surface. EDX analysis revealed that the atomic composition of the rods is Mg2Al4Si5O18. The samples exhibited diamagnetic behavior at 300 K and the magnetization increased sharply at 25 K, suggesting a ferromagnetic or ferrimagnetic transition. This type of the magnetic behavior originates from minor crystalline phases, such as MgO and MgAl2O4.