ESR and magnetization studies of Fe2O3–Bi2O3–ZnO–PbO glass system

• ESR and magnetization studies of the glass system (Fe2O3)x (70 Bi2O3 20 ZnO 10 PbO)1−x were carried out.
• ESR data shows formation of superparamagnetic clusters.
• Spin glass-like transition and a superparamagnetic blocking observed in all samples.
• The inhomogeneous distribution of magnetic moments in the glass is inferred from these studies.

The electron spin resonance (ESR) and magnetization measurements were undertaken to understand the magnetic phenomena in the glass system with composition (Fe2O3)x (70 Bi2O3 20 ZnO 10 PbO)1−x (x=15, 20 and 25 mol%). At high temperature the ESR spectra consists of narrow resonance at g~2. As the temperature decreases a second resonance peak emerges and with further decrease in temperature, the second resonance peak progressively shifts towards lower field value. The ESR data shows the formation of superparamagnetic clusters. The temperature dependent magnetization data exhibits a spin glass-like transition and a superparamagnetic blocking at a temperature which increases with increase in x value.