Pressure-induced transition from a canted antiferromagnetic state to a ferromagnetic state in YbRhSb

YbRhSb undergoes a transition at T-M1 = 2.7 K into a canted antiferromagnetic state with a small spontaneous moment of 3x10(-3) mu(B)/Yb. With increasing pressure P, T-M1(P) has a deep minimum of 2.5 K at 1.7 GPa. We have studied the pressure effect on the magnetization, resistivity and specific heat of a single crystal. With increasing pressure, the Kondo temperature estimated from the magnetic entropy decreases rapidly with increasing pressure, but remains at a constant value above 1.5 GPa. For P >= 2 GPa, the canted antiferromagnetic structure changes to a ferromagnetic one with a large moment 0.4 mu(B)/Yb lying in the orthorhombic b - c plane. A metamagnetic behavior at B parallel to a = 1.5 T remains in the ferromagnetic state. It is ascribed to the competition between the single-ion crystalline electric field anisotropy with easy direction parallel to a and the inter-site exchange interaction with easy b - c plane.