Magnetic behavior and characterization of La, Pr, and Bi substituted yttrium iron garnet

Abstract

In this study, the structural and magnetic properties of rare-earth-doped garnets, RxY3-xIG (R = La, Pr, and Bi), prepared by the solid-state route were evaluated. Ce0.25Pr0.25Bi0.15Y2.35Fe5O12, Ce0.25Pr0.25Bi0.2Y2.3Fe5O12, Ce0.15Bi0.15La0.1Y2.6Fe5O12, Ce0.15Bi0.15La0.2Y2.5Fe5O12, Ce0.15Bi0.15Dy0.2Y2.5Fe5O12 and Ce0.25Pr0.5Bi0.15Y2.1Fe5O12 were prepared and compared with each other. The structural and microstructural studies were carried out using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The magnetic behavior was identified by a vibrating sample magnetometer (VSM). The XRD results revealed that the synthesized powders have a relatively high purity. The XPS data confirmed the minute amounts of impurities. A single garnet phase with a relatively high purity was formed in all the samples. The crystallite size was estimated using high resolution-TEM images with an average size of 20 nm. The samples with Bi3+cation show the maximum value of Ms in comparison with the samples containing La3+, Dy3+, and Pr3+ at about 35.26 emu/g due to the enhancement of the super-exchange interaction and the variation of the bond length and bond angle. Instead, in the samples with La3+, Ms decreases with the minimum amount for xLa = 0.2. As the La increased from 0.1up to 0.2, the Ms decreased from 31.03 to 28.60 emu/g. By increasing the Pr3+ content from 0.25 to 0.5, Ms increased from 29.31 to 33.16 emu/g as expected based on Neelʼs theory. In addition, by comparing the samples Ce0.15Bi0.15La0.2Y2.5Fe5O12 and Ce0.15Bi0.15Dy0.2Y2.5Fe5O12, it was found that in a fixed amount of dopants the Ms of the sample containing Dy is 31.14 emu/g, which is 2.08 more than that of the sample containing La. Generally, by comparing the samples with one another, it can be figured out that the sample with the chemical composition of Ce0.25Bi0.2Pr0.25Y2.3Fe5O12 shows the maximum value of saturation magnetization.