Abstract:
In condensed matter physics, the study of magnetic frustration and quantum spin liquids
(QSLs) is driven by both fundamental curiosity and potential applications. Magnetic
frustration occurs when spin-lattice geometries prevent spins from aligning in low-energy
configurations, leading to highly degenerate ground states and exotic phenomena. This
thesis aims to uncover the principles governing magnetic frustration and QSLs in various
spin lattices through both experimental and theoretical methods.
We explore NaYbTe2O7, a compound featuring quasi-one-dimensional magnetic chains
of Yb3+ ions, which shows no long-range magnetic ordering down to 0.285 K yet displays
strong magnetic correlations indicative of a potential QSL state. Similarly, our study on
Yb2Te5O13, a Yb3+ dimer-based compound, reveals the absence of long-range magnetic
ordering down to 44 mK and the presence of dynamic spin correlations which are stable
even in the presence of 3200 Oe magnetic field, suggesting a QSL state within its dimer
lattice.
Additionally, we examine the two-dimensional rhombus spin-lattice in LiYbSiO4,
which exhibits no long-range magnetic ordering down to 44 mK but µSR measurements
unveil dynamic state below 0.5 K, supported by theoretical calculations indicating
a QSL state. The doubly ordered perovskite NaYbZnWO6, with its two-dimensional
distorted square lattice, also shows spin frustration and potential QSL behavior based on
experimental and theoretical analyses.
Furthermore, the triangular lattice-based compound Sr3CoNb2O9 demonstrates broad
antiferromagnetic anomalies and magnetization plateaus, with a dynamic state from 1.3 K
to 10 K. Theoretical studies suggest it as a potential Kitaev candidate due to its spin-orbit
entangled Jef f = 1/2 moments completing Jackeli Khaliluin criteria for a ”parallel-edge”
sharing geometry. Lastly, the hyperhoneycomb lattice-based magnet NaYbW2O8 shows
a disordered magnetic state with no long-range ordering and indications of a dynamic
magnetic state from combined experimental and theoretical studies.
Overall, our investigations across various lattice geometries and materials highlight the
intricate nature of magnetic frustration and the promising potential of these compounds as
quantum spin liquids, opening exciting avenues for future research in quantum magnetism
and information processing.
