Coexisting Magnetic Order and Cooperative Paramagnetism in the Stuffed Pyrochlore Tb_{2+x}Ti_{2-2x}Nb_xO_7

TL;DR

This study investigates the magnetic properties of the stuffed pyrochlore Tb_{2+x}Ti_{2-2x}Nb_xO_7, revealing persistent cooperative paramagnetism and coexistence with antiferromagnetic order across various compositions, using neutron scattering and magnetization measurements.

Contribution

It demonstrates that cooperative paramagnetism persists despite disorder and antiferromagnetic interactions, and reports coexistence of magnetic order and cooperative behavior in Tb3NbO7 without external stimuli.

Findings

No spin glass transition for T >= 1.5 K across compositions.

Persistent cooperative paramagnetism despite disorder.

Coexistence of antiferromagnetic order and cooperative behavior in Tb3NbO7.

Abstract

Neutron scattering and magnetization measurements have been performed on the stuffed pyrochlore system Tb2+xTi2-2xNbxO7. We find that despite the introduction of chemical disorder and increasingly antiferromagnetic interactions, a spin glass transition does not occur for T >= 1.5 K and cooperative paramagnetic behavior exists for all x. For x = 1, Tb3NbO7, an antiferromagnetically ordered state coexisting with cooperative paramagnetic behavior is seen without applying any external fields or pressure, a situation advantageous for studying this cooperative behavior.