Emergence of field-induced memory effect in spin ices

Area of Science:

• Condensed Matter Physics
• Magnetism
• Materials Science

Background:

• Strongly correlated materials exhibit complex behaviors under non-equilibrium conditions.
• Spin ices, such as Dy2Ti2O7 and Ho2Ti2O7, are known for their unique magnetic properties due to geometric frustration.

Purpose of the Study:

• To investigate the out-of-equilibrium magnetic properties of polycrystalline Dy2Ti2O7 and Ho2Ti2O7 spin ices.
• To understand the origin of anomalous hysteresis and memory effects in these materials.

Main Methods:

• Experimental investigation of magnetic properties using AC susceptibility measurements.
• Analysis of temperature and magnetic field dependence.
• Theoretical considerations of spin structure, disorder, and spin-phonon coupling.

Main Results:

• Observed magnetic field-induced anomalous hysteresis in AC susceptibility measurements.
• Demonstrated a memory effect (anomalous thermomagnetic hysteresis) dependent on thermal and non-thermal variables.
• Identified quenched disorder and suppressed spin-phonon coupling as key factors influencing magnetic behavior.

Conclusions:

• Out-of-equilibrium properties in these spin ices arise from geometric frustration, disorder, and cooperative spin dynamics.
• The observed phenomena provide insights into hidden equilibrium properties of strongly correlated materials.
• Understanding these dynamics is crucial for potential applications in information storage or quantum computing.