Spin-Glass Magnetic Properties Of A-Site Columnar-Ordered Quadruple Perovskites Y2mnga(Mn4-Xgax)O-12 With 0 <= X <= 3

Y2MnGa(Mn(4-x)Gaj(x))O-12 solid solutions were synthesized at high pressure of GPa and high temperature of similar to 1570 K for the 0 <= x <= 3 compositional range. Synchrotron X-ray and neutron powder diffraction were used to study the crystal structures and cation distributions. These solutions adopt the parent structure of the A-site columnar-ordered quadruple perovskite family with space group P4(2)/nmc (No. 137). They have lattice parameters of a = 7.36095 angstrom and c = 7.753 84 angstrom (x = 0), a = 7.361 68 angstrom and c = 7.716 16 angstrom (x = 1), a =7.360 34 angstrom and c = 7.67142 angstrom (x = 2), and a = 7.363 93 angstrom and c = 7.616 85 A (x = 3) at room temperature. The x = 0 sample has a cation distribution of [Y-2(3+)](A)[Mn3+](A)'[Ga0.683+Mn0.322+](A")[Mn3.68Ga0.32](B)O-12 with a preferred localization of Ga3+ in the tetrahedral A" site and with a small amount of Ga3+ in the octahedral B site. A complete triple A-site order, [Y-2(3+)](A)[Mn3+](A)[Ga3+](A'')-[Mn4-x3+Gax3+](B)O-12, is realized for x >= 1. All samples demonstrate spin -glass -like magnetic properties, and the absence of a long-range magnetic order at the ground state at 1.5 K was confirmed by neutron diffraction for the x = 1 sample. First-principles calculations indicated the spin-glass-like magnetic ordering is derived from the Ga substitution to the B sites and gave evidence that the ideal cation distribution could produce robust ferromagnetism in this family of perovskites.