Abstract
The magnetoresistance of a 20 mm diameter single crystal sphere of high purity aluminium was examined at 4.2K in fields up to 5 T using three electrodeless techniques (Delaney and Pippard 1972). No signs of saturation of the magnetoresistance were observed. The results obtained for the field along a cube axis were similar to those reported by Balcombe and Parker (1970). For the field far from any major symmetry direction, the magnetoresistance exhibited a weak, approximately quadratic field dependence. The possibility that this behaviour is due to magnetic breakdown is discussed in terms of a Fermi surface similar to Ashcroft's (1963) energy gap between zones.