Magnetic properties of<i>Pnma</i>- oxides (R = Sm, Eu, Dy and Ho)

Abstract

In this work, we report DC susceptibility measurements in the range 1.8 - 300 K on oxides with R = Sm, Eu, Dy and Ho. displays Van Vleck paramagnetism which corresponds to the singlet ground state of ions, with a spin - orbit coupling constant value of also behaves as a Van Vleck paramagnet, with the magnetic ground multiplet split under the crystal - field interaction. For this compound we found that the ground state corresponds to an effective spin state S , with effective magnetic moment , and Van Vleck constant . For R = Dy and Ho, the magnetic susceptibility obeys a Curie - Weiss law down to T = 1.8 K, with effective moments close to the free-ion values. The absence of magnetic ordering above 1.8 K, together with the Curie temperatures and of these compounds, indicate the existence of competing interactions that frustrate the magnetic ordering.