Structural and Dielectric Properties of MgTi_2−xSn_xO₅

MgTi_{2 − x}Sn_xO₅ has been synthesized from MgO (Periclase), TiO₂ (Anatase) and SnO₂ (Cassiterite) by ceramic conventional mixed oxide route. The presence of tin shows superlattice lines corresponding to (030) and (221) planes in addition to karrooite phase. Both the FTIR spectral analysis and X-ray intensity analysis indicate that the structural properties optimize at x = 0.2. The dielectric constant (K′) and the relative dielectric loss (K″) as well as tan δ have been measured as a function of frequency as well as temperature. The dielectric hysteresis loop is attributed to order-disorder transition. On the basis of these observations it is concluded that small value of dielectric constant is attributed to 1) migrational polarization and 2) cation disorder. Following the researcher's interest in dependence of cation disorder in MgTi₂O₅ on pressure, the variation of dielectric constant as a function of pressure has been measured. On the basis of these measurements, it is concluded that these materials may prove to be potential pressure sensors.

Keywords:

• Karrooite
• cation-disorder
• dielectric

Acknowledgments

Paper originally presented at AMF-4, Bangalore, India, December 12-15, 2003.