Evidence of the spin gap in Hg0.9Tl0.1Ba2Ca2Cu3O8+δ

Abstract We have measured the resistivity ϱ(T) in high quality Hg 0.9 Tl 0.1 Ba 2 Ca 2 Cu 3 O 8+δ thin films and specific heat in Hg 0.9 Tl 0.1 Ba 2 Ca 2 Cu 3 O 8+δ polycrystals samples. The resistivities ϱ ab (T) in the thin film samples show systematic deviation from T-linear behavior below a temperature T D well above T c . The magnitude of the specific heat jump δγ(T c ) decreases sharply with little change in T c or in γ(T) well below or well above T c . Those behaviors reflect the opening of the spin gap.