Study of Magnetic Properties of A_2B^'NbO_6 (A=Ba,Sr, (BaSr): and B^'=Fe and Mn) double perovskites

TL;DR

This study investigates the magnetic behaviors of specific double perovskites, revealing antiferromagnetic and multiple magnetic transitions, with ESR measurements indicating no Jahn-Teller distortion in Mn compounds.

Contribution

It provides new insights into the magnetic properties and transition behaviors of A_2B'NbO_6 double perovskites with different A-site ions.

Findings

Ba_2FeNbO_6 is an antiferromagnet with weak ferromagnetism at 5K.

Ba_2MnNbO_6 exhibits two magnetic transitions at 45K and 12K.

Mn compound shows no Jahn-Teller distortion in ESR measurements.

Abstract

We have studied the magnetic properties of Ba_2FeNbO_6 and Ba_2MnNbO_6. it is seen that Ba_2FeNbO_6 is an antiferromagnet with a weak ferromagnetic behaviour at 5K while Ba_2MnNbO_6 shows two magnetic transitions one at 45 K and the other at 12K. Electron spin resonance (ESR) measurements at room temperature show that the Mn compound does not show any Jahn-Teller distortion. It is also seen that the Neel temperature of the A_2FeNbO_6 (A=Ba,Sr, BaSr) compounds do not vary significantly. However variations in the average A-site ionic radius influence the formation of short range correlations that persist above T_N.