Collective modes and sound propagation in a magnetic field in superfluid /sup 3/He-B
A high-resolution, ultrasonic (12-89 MHz) acoustic impedance technique has been used to investigate the order parameter collective modes in superfluid /sup 3/He-B over a pressure range of 0-15 bar and in magnetic fields up to 180 mT. In agreement with earlier experiments, the J = 2 real squashing mode has been observed to split into five components in small magnetic fields. However, contrary to earlier theoretical estimates, the Zeeman shifts have been found to become extremely nonlinear as the magnetic field is increased. The extent of this nonlinearity is largest at low pressures and at temperatures close to T/sub c/. In comparison with recent theoretical work, the nonlinear Zeeman shifts may be explained as a result of two effects. First, there is a significant distortion of the B-phase energy gap in large magnetic fields. Second, there is an important coupling between the J/sub z/ substates of the different J modes. In this sense the nonlinear evolution of the real squashing mode constitutes the observation of the Paschen-Back effect in /sup 3/He-B.
- Research Organization:
- Department of Physics and Astronomy and Materials Research Center, Northwestern University, Evanston, Illinois
- OSTI ID:
- 5611221
- Journal Information:
- J. Low Temp. Phys.; (United States), Vol. 63:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HELIUM 3 B
ORDER PARAMETERS
ULTRASONIC WAVES
COLLECTIVE EXCITATIONS
MAGNETIC FIELDS
NONLINEAR PROBLEMS
WAVE PROPAGATION
ZEEMAN EFFECT
ENERGY-LEVEL TRANSITIONS
EVEN-ODD NUCLEI
EXCITATION
HELIUM 3
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
SOUND WAVES
STABLE ISOTOPES
640450* - Fluid Physics- Superfluidity