  We present experimental results of transverse electron-focusing measurements
performed using n-type GaAs. In the presence of a small transverse magnetic
field (B), electrons are focused from the injector to detector leading to
focusing peaks periodic in B. We show that the odd-focusing peaks exhibit a
split, where each sub-peak represents a population of a particular spin branch
emanating from the injector. The temperature dependence reveals that the peak
splitting is well defined at low temperature whereas it smears out at high
temperature indicating the exchange-driven spin polarisation in the injector is
dominant at low temperatures.
