Microwave and magneto-optic properties of ε-Fe2O3 nanoparticles arising in borate glasses doped with Fe and Gd

Oxana Ivanova,Janis Kliava,Irina Edelman,Eleonora Petrakovskaja,Ruslan Ivantsov,N Perov,A Semisalova

doi:10.1051/epjconf/201818503011

Abstract

The ε-Fe2O3 nanoparticles in borate glasses co-doped with low concentrations of Fe2O3 and Gd2O3 were investigated with two experimental techniques – visible magnetic circular dichroism (MCD) and electron spin resonance (ESR). The most prominent features of the MCD spectra are: non-linear dependence of the spectral maxima intensities on the Gd concentration and strong increase with the temperature decrease. The ESR spectra of these glasses exhibit two features with g = 4.3 due to the diluted Fe3+ ions and 2.0 associated both with Fe3+ ions and with nanoparticles. The integrated spectra intensities do not follow the T-1 Curie law suggesting a considerable contribution from the magnetically ordered nanoparticles to ESR. Analysis of the MCD and ESR concentration dependences allow suggestion on the Gd ions incorporation into nanoparticles.

Highlights

Iron oxides are among the most used metal oxides with various applications in different scientific and industrial fields
We have undertaken a study of these glasses with two experimental techniques – visible magnetic circular dichroism (MCD) and electron spin resonance (ESR)
The nanoparticles morphology and structure, and the elements distribution in a glass were studied with electron microscope JEM-2200FS, energy dispersive Xray analysis (EDX), Fast Fourier transform (FFT)

Summary

Introduction

Iron oxides are among the most used metal oxides with various applications in different scientific and industrial fields. Structure and physical properties of the nanoparticles were shown to depend critically on the technology which creates difficulties in the identification of the particular iron oxide phase. This is especially important in the case of ε-Fe2O3 nanoparticles (e.g., [37]). The role of Gd in the formation of nanoparticles and its localization in the glass remained unclear To elucidate these questions, we have undertaken a study of these glasses with two experimental techniques – visible magnetic circular dichroism (MCD) and electron spin resonance (ESR). MCD is associated, mainly, with magnetically ordered phases while ESR includes a contribution of diluted paramagnetic ions, as well These methods are expected to provide consistent and complementary data

Experimental detail

Results and discussion

Conclusions