Crystallization kinetics and magnetic properties of iron oxide contained 25Li2O -8MnO2 -20CaO -2P2O5 -45SiO2 glasses

With crystallisation at 850 C for 4 h, LiMn2O4, beta-wollastonite (beta-CaSiO3), lithium silicate (Li2SiO3), Ca(Ca,Mn)Si2O6 and Li2Ca4Si4O13 phases were found in 25Li2O-8MnO2-20CaO-2P2O5-45SiO2 (LMCPS) glass-ceramics. The (Li,Mn) ferrite phase was obtained in the iron oxide containing LMFCPS glass-ceramic and Li2FeMn3O8 phase was found in that containing 8 at% Fe2O3. TEM investigations showed that (Li,Mn) ferrite particles dispersed in the beta-wollastonite matrix (Li,Mn) ferrite particles, with an average size of 40 nm, were found in the glass-ceramics containing 4 at% Fe2O3. The (Li,Mn) ferrite particle sizes in the glass-ceramics containing 8 at% Fe2O3 varied from a few micron to 5 nm. The SQUID result showed that only the glass-ceramic containing 4 at% Fe2O3 exhibited super-paramagnetic behaviour at 300 K and ferromagnetic behaviour at 4 K. The LMCPS glass-ceramic containing 8 at% Fe2O3 exhibited ferromagnetic behaviour at both temperatures. 22 refs.