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

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 $\le$ x $\le$ 1.9), show spin freezing (T $\sim$ 17 K) similar to the field induced spin ice freezing for low La compositions (0 $\le$ x $\le$ 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 $\le$ x $\le$ 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.

14 pages, 15 figures, 2 tables