Magnetic and electrical properties of layered magnets Tl(Cr,Mn,Co)Se2

Tl(Cr,Mn,Co)Se2 crystals were synthesized at T ∼ 1050 K. X-ray diffraction analysis showed that TlCrSe2, TlMnSe2, and TlCoSe2 compounds crystallize in the hexagonal crystal system with the lattice parameters: a = 3.6999 A, c = 22.6901 A, c/a ∼ 6.133, z = 3, ρx = 6.209 g/cm3; a = 6.53 A, c = 23.96 A, c/a ∼ 3.669, z = 8, ρx = 6.71 g/cm3; and a = 3.747 A, c = 22.772 A, c/a ∼ 6.077, z = 3, ρx = 7.577 g/cm3, respectively. Magnetic and electrical studies in the temperature range from 80-400 K showed that TlCrSe2 is a semiconductor ferromagnet, TlMnSe2 is a semiconductor antiferromagnet, and TlCoSe2 is a ferrimagnet with a conductivity characteristic of metals. A rather large deviation in the experimental effective magnetic moment for TlCrSe2 (3.05 μB) from the theoretical value (3.85 μB) is attributed to two-dimensional magnetic ordering in the paramagnetic region of the noticeably layered ferromagnet TlCrSe2. In TlCrSe2, a correlation between magnetic and electrical properties was detected.