Emergence of Spin Ice freezing in Dy$_2$Ti$_{1.8}$Mn$_{0.2}$O$_7$

Rajnikant Upadhyay; Manjari Shukla; Rachana Sain; Martin Tolkiehn; Chandan Upadhyay

paper

Emergence of Spin Ice freezing in Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$

arXiv:2205.04140

Abstract

We herein present the spin freezing dynamics of stuffed polycrystalline compound Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$ . In Dy $_{2}$ Ti $_{2}$ O $_{7}$ , spin freezes with ice-like spin relaxations at a temperature around 3 K (T $_{i}$ ) along with another spin freezing at a temperature around 0.7 K (T\textless T $_{i}$ ). These relaxations can be observed prominently with an application of varying DC magnetic field bias and applied AC-field. We show here that with fractional inclusion of Mn at the Ti site in Dy $_{2}$ Ti $_{2}$ O $_{7}$ , there is a significant shift in these temperatures. In Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$ the T $_{i}$ shifts to a higher temperature around 5 K and freezing belonging to T\textless T $_{i}$ shifts to 2.5 K without any application of external DC Bias and/or AC-field. The inclusion of Mn at Ti site also enhances the ferromagnetic interaction for Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$ as compared to Dy $_{2}$ Ti $_{2}$ O $_{7}$ . Arrhenius fit of freezing temperature with frequency for Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$ shows that these spin relaxations at T $_{i}$ and T\textless T $_{i}$ are thermally induced. Low-temperature structural change in lattice parameters and crystal field phonon coupling has been studied using synchrotron x-ray diffraction. Debye-Gruineisen analysis of temperature-dependent lattice volume shows the emergence of crystal field phonon coupling at a much higher temperature (70 K) in Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$ in contrast to 40 K in Dy $_{2}$ Ti $_{2}$ O $_{7}$ . These findings make Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$ a suitable system to explore the application of the spin ice phenomenon at a workable temperature.

6 pages, 9 figures

Emergence of Spin Ice freezing in Dy2​Ti1.8​Mn0.2​O7​

Abstract

Emergence of Spin Ice freezing in Dy $_{2}$ Ti $_{1.8}$ Mn $_{0.2}$ O $_{7}$