Evolution of spin freezing transition and structural, magnetic phase diagram of Dy$_{2-x}$La$_x$Zr$_2$O$_7$; $x$ = 0-2.0

TL;DR

This study investigates how La substitution affects the structural and magnetic phase transitions in Dy$_{2-x}$La$_x$Zr$_2$O$_7$, revealing spin ice freezing and spin glass states depending on composition.

Contribution

It provides new insights into the evolution of spin freezing and magnetic phases in Dy$_{2-x}$La$_x$Zr$_2$O$_7$ with La substitution, including phase stabilization and magnetic state transitions.

Findings

Higher La compositions show spin freezing similar to known spin ice systems.

Low temperature magnetic state transitions to spin glass below 6 K for high La content.

Narrow distribution of spin relaxation times observed in these compounds.

Abstract

Dy$_{2}$Zr$_{2}$O$_{7}$ a disordered pyrochlore system, exhibits the spin ice freezing under the application of magnetic field. Our studies suggest the stabilization of pyrochlore phase in Dy$_{2-x}$La$_{x}$Zr$_{2}$O$_{7}$ with the substitution of nonmagnetic La, along with the biphasic mixture for the intermediate compositions. We observed that the higher La compositions (1.5 $\leq$ x $\leq$ 1.9), show spin freezing (T $\sim$ 17 K) similar to the field induced spin ice freezing for low La compositions (0 $\leq$ x $\leq$ 0.5), and the well known spin ice systems Dy$_{2}$Ti$_{2}$O$_{7}$ and Ho$_{2}$Ti$_{2}$O$_{7}$. The low temperature magnetic state for higher La compositions (1.5 $\leq$ x $\leq$ 1.9) culminates into spin glass state below 6 K. The Cole-Cole plot and Casimir-du Pr$\acute{e}$ fit shows narrow distribution of spin relaxation time in these compounds.