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

In this paper it is demonstrated that the second phase transition of Gd₂In intermetallic compound gets eliminated by diluting Gd_2−x(LaY)_xIn at a critical composition of x=0.5. The exchange coupling for intra-cluster interactions is estimated in the correlation ranges of 3.3 Å<R_C<3.6 Å (anisotropic source) and for inter-cluster interactions in the ranges of R_C>4 Å where the correlation length is defined as . 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.