Investigation and Improvement of the Physical Properties of Multiferroic with Formula Lat-xShxFe03

Abstract

It is well know that Lanthanum orthoferrite LaFe03 has an antiferromagnetic behavior and BiFe03 is a typical multiferroic. Therefore, we expected that doping LaFe03 by antimony (Sb) which lies in the same group with Bi in the periodic table gives good electric properties for LaFeOJ keeping high magnetic properties. Consequently, we will achieve multiferroic behavior.

The experimental steps in the thesis are summarized into the following: preparation and characterization of La orthoferrite system. Improvement of ferroelectric like behavior of the orthoferrite under investigation by the partial replacement of Sb3+ instead of La3+.

A correlation between structural, magnetic and electric properties will be established to outline the enhancement of the properties of the prepared samples. Examination of the multiferroic behavior of the samples will open a new era of many applications.

The techniques and characterization methods used in this study are: Structural analysis using X-ray diffraction (XRD), Spectroscopic analysis using Fourier transform infra red (FTIR) and transmission electron microscope (TEM). Magnetic properties by measuring magnetic susceptibility using the Faraday's methods were measured. Magnetic hysteresis at different temperatures and magnetic field intensities and the electrical properties by measuring dielectric constant, dielectric loss, ac conductivity, Seebeck voltage coefficient was also measured.

The thesis consists of two groups. The effect of the substitution of Sb+J ions instead of La+3 ions was studied in the first group of the formula La .xSbxFe03 (0 :"::

x ::; 0.3, step 0.05) where the parent is LaFe03. From XRD the samples with Sb+J content (x) 0.0, 0.05 and 0.1 were formed in single phase, but the samples with x > 0.1 have a small secondary phase from Sb203.