Effect of Y3+, Bi3+, La3+substitution on structural, optical and magnetic properties of gadolinium iron garnets

The samples of Y0.2Bi0.2LaxGd2.6-xFe5O12 (x = 0, 0.2 and 0.4) were successfully prepared by sol-gel auto combustion method. X-ray diffraction (XRD) study reveals that garnet phase is dominant in all prepared samples. The crystallite size of the samples is in 33-54 nm range. The crystallite size varies with varying La+3+substitution in the samples. The calculated grain size of the samples is in 0.100 to 0.116 lm range. Energy dispersive X-ray (EDX) mapping confirms the presence of all elements in the formed samples. From Ultraviolet- Visible (UV-VIS) spectroscopy it has been found that the samples have wide band gap (3.7 eV to 3.9 eV) which suggests that such materials can be operated in higher temperature, voltage and frequency. This makes these materials suitable in military application. From vibrating sample magnetometer (VSM) it has been clear that addition of La3+ changes the value of coercivity (Hc) and magnetic saturation (Ms) which make these materials suitable for switching devices and for antenna applications. The value of operating microwave frequency (xm) suggests the use of such materials in devices operated in Ultra High frequency region.