Magnetic Studies on Eu3MO7 (M = Nb, Ta, Ir) with Fluorite-related Structure by Eu-151 Mossbauer Spectroscopy and Magnetic Susceptibility Measurements

摘要

Magnetic properties of europium-containing compounds Eu3MO7 (M = Nb, Ta, Ir) with fluorite-related structure have been investigated. Magnetic susceptibility measurements show that all these compounds are paramagnetic and have no magnetic ordering down to 1.8 K. At very low temperatures (T 50 K), the susceptibilities of each compound attain constant values, which is characteristic of the ground state for Eu3+ ions. The results of Eu-151 Mossbauer spectroscopic measurements show that the asymmetric parameter for Eu(2) in seven-coordination is much larger than that for Eu(1) in cubic environment, which in accordance with the crystallographic result.