STRUCTURAL AND MAGNETIC PROPERTIES OF GLASSYPHOSPHATES WITH NASICON-LIKE FRAMEWORK

摘要

The structural and magnetic properties of vitreous materials containingtransition metal cations – Li_xM_2(PO_4)_x (M = Fe, V, Mo and 3, 5, 6,respectively) which crystallize with the Nasicon-like structure have beenstudied. Information concerning local cationic environments andconfiguration of (PO_4)~(3-)polyanions and P-O-P bridges have beenconcluded from Raman and Fourier Transform Infrared (FTIR)spectroscopy investigations. The vibrational spectrum of Li_xM_2(PO_4)_xisdominated by two very strong and broad bands located in mid-infrared andin the far-infrared range. A third band is attributed to the P-O-P ring ofP205 glass former. Studies of the magnetic susceptibility have been carriedout by Superconducting Quantum Interference Device (SQUID)measurements. Temperature dependence of magnetic susceptibility of thesamples with Fe- and V- containing compounds follows a Curie-Weissmodel at room-temperature and below down to Neel point. For the Mo-based compounds, a different behavior has been observed; this materialbehaves as diamagnetic in the whole range of temperature.