Temperature dependence of metamagnetic transition in YbB12

Kondo semiconductor YbB12 shows metamagnetic transition with a large jump o f magnetization at the field of 47 T along [1 0 0] and at 53 T along [1 1 0 ] and [1 1 1]. Resistivity decreases with increasing field and shows steep decrease at the transition held. By towering temperature down to 88 mK, a f ew peaks and shoulders appear in the magnetoresistance curve along [1 0 0] and [1 1 1] below the transition field which may indicate that the density of state is not a simple structure in the band gap. The anisotropic magneto resistance in YbB12 at various temperatures is reported. (C) 2000 Elsevier Science B.V. All rights reserved.