Novel isotope effects observed in polarization echo experiments in glasses

Area of Science:

• Condensed Matter Physics
• Materials Science
• Low-Temperature Physics

Background:

• Dielectric measurements on insulating glasses at very low temperatures have revealed unexpected magnetic field effects.
• Polarization echo experiments suggest atomic tunneling systems and their nuclear properties are responsible for these phenomena.
• It has been hypothesized that nuclear quadrupole moments of tunneling systems cause these magnetic field effects.

Purpose of the Study:

• To investigate the role of nuclear quadrupole moments in magnetic field effects in insulating glasses.
• To examine the isotope effect in polarization echo experiments using deuterated and ordinary glycerol.
• To explore new phenomena in spontaneous echo decay in zero magnetic field.

Main Methods:

• Conducting dielectric measurements on insulating glasses at very low temperatures.
• Performing polarization echo experiments on fully deuterated and ordinary glycerol.
• Analyzing spontaneous echo decay in zero magnetic field.

Main Results:

• The study clearly demonstrated the crucial role of nuclear quadrupole moments in magnetic field effects through isotope studies.
• A new effect was observed in the decay of spontaneous echoes in zero magnetic field for deuterated glycerol samples.
• This new effect is explained by quantum beating involving quadrupole levels.

Conclusions:

• Nuclear quadrupole moments are definitively shown to be critical for magnetic field effects in dielectric measurements of insulating glasses.
• The findings provide strong evidence for the involvement of nuclear properties in low-temperature dielectric phenomena.
• A novel quantum beating phenomenon related to quadrupole levels was identified in deuterated glycerol.