COMPOSITE FERMIONS AROUND LANDAU-LEVEL FILLING FACTOR NU=3 2/

Our magnetotransport experiments on a low-density two-dimensional elec tron sample detect an alternating strength of the fractional quantum H all effect (FQHE) states around Landau level filling factor nu=3/2 as the magnetic field is moving away from nu=3/2. This is viewed as a man ifestation of spin-split levels of composite fermions around nu=3/2. A cyclotron effective mass m(cf)approximate to 0.4m(0) (where m(0) is the free electron mass) of composite fermions around nu=3/2 is deduced from Shubnikov-de Haas oscillations in a tilted (theta=73 degrees) ma gnetic field. This value is found to be in keeping with a mass of m(cf )approximate to 0.7m(0) determined around nu=1/2 in the same sample o nce the root B-dependence is taken into account.