Temperature dependent Raman and x-ray studies of spin-ice pyrochlore $D{y}_{2}T{i}_2{O}_7$ and non-magnetic pyrochlore $L{u}_{2}T{i}_2{O}_7$

Abstract

We present here temperature-dependent Raman, x-ray diffraction and specific heat studies between room temperature and 12 K on single crystals of spin-ice pyrochlore compound $D{y}_{2}T{i}_2{O}_7$ and its non-magnetic analogue $L{u}_{2}T{i}_2{O}_7$. Raman data show a "new" band not predicted by factor group analysis of Raman-active modes for the pyrochlore structure in $D{y}_{2}T{i}_2{O}_7$, appearing below a temperature of $T_c=$110 K with a concomitant contraction of the cubic unit cell volume as determined from the powder x-ray diffraction analysis. Low temperature Raman experiments on O${}^{18}$-isotope substituted $D{y}_{2}T{i}_2{O}_7$ confirm the phonon origin of the "new" mode. These findings, absent in $L{u}_{2}T{i}_2{O}_7$, suggest that the room temperature cubic lattice of the pyrochlore $D{y}_{2}T{i}_2{O}_7$ undergoes a "subtle" structural transformation near $T_c$. We find anomalous \textit{red-shift} of some of the phonon modes in both the $D{y}_{2}T{i}_2{O}_7$ and the $L{u}_{2}T{i}_2{O}_7$ as the temperature decreases, which is attributed to strong phonon-phonon anharmonic interactions.

28 pages, 9 figures (Accepted for publication in Physical Review B)

References in corpus (10)

• Er2Ti2O7: Evidence of Order by Disorder in a Frustrated Antiferromagnet
• Magnetic anisotropy of the spin ice compound Dy2Ti2O7
• Magnetic order and spin fluctuations in the spin liquid Tb$\_2$Sn$\_2$O$\_7$
• Crystal structure of the pyrochlore oxide superconductor KOs${}_2$O${}_6$
• Phonon and crystal field excitations in geometrically frustrated rare earth titanates
• Manifestation of geometric frustration on magnetic and thermodynamic properties of pyrochlores $S{m}_2{X}_2{O}_7$ (X=Ti, Zr)
• Structural properties of the geometrically frustrated pyrochlore Tb2Ti2O7
• Far-infrared optical properties of the pyrochlore spin ice compound Dy2Ti2O4
• High-temperature spin relaxation process in Dy${}_2$Ti${}_2$O${}_7$ probed by ${}^{47}$Ti-NQR
• Ordered spin-ice state in the geometrically frustrated metallic-ferromagnet Sm2Mo2O7

Cited by in corpus (10)

• Low temperature and high pressure Raman and x-ray studies of pyrochlore Tb${}_2$Ti${}_2$O${}_7$ : phonon anomalies and possible phase transition
• Structural, optical and mechanical properties of Y2Ti2O7 single crystal
• Thermal Conductivity and Specific Heat of the Spin-Ice Compound Dy${}_2$Ti${}_2$O${}_7$: Experimental Evidence for Monopole Heat Transport
• Spin-phonon coupling in hole-doped pyrochlore iridates Y${}_2$(Ir${}_{1-x}$Ru${}_x$)${}_2$O${}_7$: A Raman scattering study
• Coexistence of metallic and nonmetallic properties in the pyrochlore Lu${}_2$Rh${}_2$O${}_7$
• Effect of phonon anharmonicity on ferroelectricity in EuxBa1-xTiO3
• Raman and photoluminescence spectroscopic studies on structural disorder in oxygen deficient Gd2Ti2O7-d single crystals
• Experimental observation of magnetoelectricity in spin ice Dy${}_2$Ti${}_2$O${}_7$
• Nonmagnetic substitution in pyrochlore iridate Y${}_2$(Ir${}_{1-x}$Ti${}_x$)${}_2$O${}_7$: Structure, magnetism and electronic properties
• Ultrafast Dynamics of Spin-Orbit Entangled Excitons Coupled to Magnetic Ordering in van der Waals Antiferromagnet NiPS3