Mössbauer Studies and Magnetic Properties of Y_3−x Ce _x Fe₅O₁₂

Abstract

Magnetic and crystallographic properites of Y_3−x Ce _x Fe₅O₁₂ (x = 0.0, 0.1, and 0.3) have been studied with X-ray diffraction, vibrating sample magnetometer (VSM), and Mössbauer spectroscopy. A small coercivity (H _c = 5.8 Oe), was obtained for the sample Y_2.9Ce_0.1Fe₅O₁₂, which is comparable to that of an undoped sample Y₃Fe₅O₁₂ (H _c = 54.1 Oe). Mössbauer spectra of Y_3−x Ce _x Fe₅O₁₂ were measured at various absorber temperatures from 4.2 K to Néel temperature. It is found that Debye temperatures of octahedral (16a) and tetrahedral (24d) site for Y_2.9Ce_0.1Fe₅O₁₂ are Θ _a = 353, Θ _d = 464 K, respectively,and for Y_2.7Ce_0.3Fe₅O₁₂, Θ _a = 380, Θ _d = 444 K, respectively. The intersublattice a-d superexchange interaction was found to be antiferromagnetic with the strength of J _{a− d} = −21.42 kg, while the intrasublattice interactions a-a,d−d were found to be ferromagnetic with strengths of J _{a− a} =4.50 k _B and J _{d− d} = 0.02k _B, respectively, in the sample Y_2.9Ce_0.1Fe₅O₁₂.