Low temperature Spin freezing and Diffuse Magnetic Correlations in Tb$_{2}$Zr$_{2-x}$Ti$_{x}$O$_{7}$ (x = 0, 0.5)

TL;DR

This study investigates the low-temperature magnetic behavior and short-range correlations in Tb$_{2}$Zr$_{2-x}$Ti$_{x}$O$_{7}$ compounds, revealing spin freezing, diffuse scattering, and disorder effects in frustrated pyrochlore systems.

Contribution

It provides new insights into how structural disorder and Ti doping influence magnetic states and correlations in Tb-based pyrochlores.

Findings

No long-range magnetic order down to 0.4 K.

Spin freezing occurs below 1.25 K and 1.05 K for parent and doped compounds.

Diffuse neutron scattering indicates persistent short-range correlations.

Abstract

Structural disorder in the magnetically frustrated pyrochlore system leads to intriguing magnetic states. We present the thermodynamic behavior and short range magnetic correlations in Tb$_{2}$Zr$_{2}$O$_{7}$ and Tb$_{2}$Zr$_{1.5}$Ti$_{0.5}$O$_{7}$ compounds. The parent compound Tb$_{2}$Zr$_{2}$O$_{7}$ has defect fluorite structure, which evolves toward the pyrochlore phase on Ti doping at Zr site. There is no long range magnetic order down to 0.4 K, and a magnetic field dependent spin freezing evolves below 1.25 K and 1.05 K for the parent and doped compounds, respectively. The ac susceptibility measurements indicate slow spin relaxation process below 20 K in these compounds. Inelastic neutron scattering reveals broad diffuse scattering, indicative of short range correlations at low temperature, owing to local structural distortions and persistent spin fluctuations. These results suggest a correlated, disorder influenced magnetic state in Tb$_{2}$Zr$_{2}$O$_{7}$, Tb$_{2}$Zr$_{1.5}$Ti$_{0.5}$O$_{7}$ compounds.