Fumihiro Kariya

Spin-glass characteristics in the quaternary spinel-type Ag(Cr1-xSnx)2S4

A few spinel compounds exist with the occupation of Ag atom on tetrahedral (or A) sites and have been less extensively studied. It is hard to synthesize high purity specimens of Ag-based thiospinels. The substituted quaternary spinel compounds Ag(Cr1-xSnx)2S4 (x = 0.50, 0.60, and 0.70) have been successfully prepared. These compounds exhibit the spin-glass nature with the freezing temperature Tg = 18.0, 15.4, and 11.4 K, respectively, where the irreversibility arises between ZFC (zero-field-cooled) and FC (field-cooled) magnetization with decreasing temperature. The asymptotic Weiss temperature θ has small value, which indicates a spin-glass magnetic property. The effective moment peff per Cr-atom is close to the spin only value for Cr3+ ion. These values are θ = – 0.90 K, peff = 3.92 Cr-atom-1 for x = 0.50; θ = 1.96 K, peff = 3.90 Cr-atom-1 for x = 0.60; and 8 = – 4.07 K, peff = 3.87 Cr-atom-1 for x = 0.70. The random distribution of Cr and Sn atoms on octahedral (or B) sites can introduce magnetic frustration. The spin frustration is due to the competition between ferromagnetic and antiferromagnetic interactions. A collinear spin alignment is inhibited in Ag(Cr1-xSnx)2S4.