Dynamical splayed ferromagnetic ground state in the quantum spin ice Yb(2)Sn(2)O(7)

Area of Science:

• Condensed Matter Physics
• Magnetism
• Materials Science

Background:

• Pyrochlore oxides are known for complex magnetic behaviors due to geometric frustration.
• Understanding exotic magnetic states in rare-earth compounds is crucial for novel electronic applications.

Purpose of the Study:

• To investigate the low-temperature magnetic ordering in polycrystalline Ytterbium stannate (Yb2Sn2O7).
• To characterize the nature of the magnetic ground state and its associated dynamics.

Main Methods:

• Magnetic susceptibility measurements.
• Specific heat capacity analysis.
• Mössbauer spectroscopy using Ytterbium-170 (170Yb).
• Neutron diffraction studies.
• Muon spin relaxation (μSR) experiments.

Main Results:

• A first-order magnetic phase transition was observed at 0.15 K.
• Long-range magnetic order was confirmed, with each Ytterbium (Yb3+) ion possessing a moment of 1.1 μB.
• A novel noncoplanar magnetic structure, termed 'splayed ferromagnetism', was identified, featuring four sublattices with moments canted relative to a cubic axis.
• The magnetic ground state exhibits dynamical fluctuations in the megahertz range.

Conclusions:

• The study reveals a unique 'splayed ferromagnetism' ground state in Yb2Sn2O7, distinct from typical magnetic orders.
• The observed magnetic anisotropy favors the local threefold axis, consistent with theoretical models for pyrochlore lattices.
• The findings provide critical experimental data for understanding magnetic frustration and phase diagrams in rare-earth pyrochlores.