Spin-glass-like behaviour in tin doped ZnCr2Se4 single crystals.

The single crystals of ZnCr 2 Se 4 doped with tin ions having contents of 0.92, 1.01 and 1.26 located in the octahedral sites of the spinel structure were successfully synthesized. The ac and dc magnetic measurements, and as well as the specific heat studies showed the spin-glass-like behaviour for all compositions below the freezing temperatures T f = 13–15 K. Both high positive values of the paramagnetic Curie–Weiss temperature, decreasing from 112 K to 58 K as the Sn-content increases, and the lack of a metamagnetic transition (characteristic for the ZnCr 2 Se 4 matrix) suggest a strong ferromagnetic exchange in the (0 0 1) planes which is randomly frozen below T f between the spins in adjacent (0 0 1) planes. These effects are interpreted in terms of the exchange integral of the spin-glass system including non-stoichiometry, spin and structural defects. [ABSTRACT FROM AUTHOR]