Percolation threshold near the second phase transition in diluted system of Gd2−x(La, Y)xIn

Abstract In this paper it is demonstrated that the second phase transition of Gd 2 In intermetallic compound gets eliminated by diluting Gd 2− x (LaY) x In at a critical composition of x =0.5. The exchange coupling for intra-cluster interactions is estimated in the correlation ranges of 3.3 A R C R C >4 A where the correlation length is defined as R C = k F | R ⇒ i - R ⇒ j | . The sign and strength of the exchange coupling are identified by the eigenvalues λ ( k ) and are obtained from zeros of the 4×4 matrix of J ij RR ′ along the three directions of the reciprocal lattice for each dilution ( x =0.25, 0.5, 0.75, 1). The transition temperature is calculated using the minimum eigenvalue λ min ( k =0, π ) which agrees with the experiment. Magnetic field and temperature dependence of the magnetization and electrical resistivity measurements show that: (i) Elimination of the AFM phase is caused by breaking of some FM short-range exchange couplings, and (ii) Conduction electrons order antiferromagnetically at low temperatures and ferromagnetically at high temperatures.