Structure and magnetic studies of geometrically frustrated disordered pyrochlores A$_{2}$Zr$_{2}$O$_{7}$: (A = Eu, Gd, Er)

TL;DR

This study investigates the structural and magnetic properties of disordered A$_{2}$Zr$_{2}$O$_{7}$ pyrochlores (A = Eu, Gd, Er), revealing how magnetic field influences spin-freezing behavior and highlighting differences from titanate counterparts.

Contribution

It provides new insights into how disordered parameters and magnetic fields affect spin dynamics in A$_{2}$Zr$_{2}$O$_{7}$ pyrochlores, expanding understanding beyond titanate systems.

Findings

Spin-freezing behavior can be retained by applying magnetic fields.

Modification at the rare earth site does not significantly alter the magnetic ground state.

Disordered parameters influence spin dynamics and freezing phenomena.

Abstract

The spin ice system Dy$_{2}$Ti$_{2}$O$_{7}$ exhibits strong frequency-dependent spin-freezing at $\sim$ 16 K temperature. Although it has been a matter of discussion for years, the origin of this unusual spin freezing is still unknown. The replacement of Ti with isovalent Zr leads to the dynamic magnetic ground state at low temperatures in Dy$_{2}$Zr$_{2}$O$_{7}$ and prevents the formation of high-temperature spin freezing. Interestingly the high-temperature spin freezing re-emerges in the presence of the magnetic field. In this direction, we have studied a series of disordered pyrochlore oxides A$_{2}$Zr$_{2}$O$_{7}$ (A = Eu, Gd, Er) and compared their crystal structure, magnetic, and heat capacity behavior with that of Dy$_{2}$Zr$_{2}$O$_{7}$ and Ho$_{2}$Zr$_{2}$O$_{7}$ systems. Our study shows that depending on the disordered parameter, the spin-freezing behavior can be retained by slowing down the spin dynamic with a suitable choice of the magnetic field. We observe that unlike titanates, modification at the rare earth site does not make considerable change in the magnetic ground state of these zirconates compounds.