engleski

Structural and magnetic study of iron phosphate glass and glass-ceramics

Iron phosphate glass exhibits the spin-glass behavior and represents a prototype glass with disordered spatially distributed magnetic moments. Since the iron ions in glass are present in two valence states (Fe2+ and Fe3+) changes in magnetic properties, during the change of valence and local surroundings of iron ions, are expected. The purpose of the present study was to investigate the influence of controlled crystallization on structure and magnetic properties in iron phosphate glass and glass-ceramics. The 40Fe2O3-60P2O5 (mol%) glass was crystallized by heat treatments at 620, 650 and 800 °C for 24 h. The evolution of crystalline phases in glass-ceramics was studied by X-ray diffraction (XRD) and Raman spectroscopy, whereas, magnetic properties were studied by means of vibrating sample magnetometer (VSM). The XRD and Raman analysis showed change of the structure from glassy to crystallized samples with different iron phosphate crystalline phases: Fe3(P2O7)2, Fe4(P2O7)3, Fe(PO3)3 and FePO4. Investigation of magnetic nature of prepared glass and glass-ceramics showed dominant antiferromagnetic interactions, demonstrated by the characteristic cusps in the susceptibilities at low temperature and the negative values of the paramagnetic temperatures. Magnetic interactions involving iron ions were revealed depending on the different crystalline phases present in glass- ceramics.

IPG; spin-glass; structure

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