Ferromagnetic-phase transition in the spinel-type CuCr2Te4

Ferromagnetic-phase transition in spinel-type CuCr 2 Te 4 has been clearly observed. CuCr 2 Te 4 is a telluride–spinel with the lattice constant a = 11.134 A , which has been synthesized successfully. The heat capacity exhibits a sharp peak due to the ferromagnetic-phase transition with the Curie temperature T C = 326 K . This value of T C corresponds exactly to that of the negative peak of d M /d T in low field of 1.0 Oe. The magnetic susceptibility shows the Curie–Weiss behavior between 380 and 650 K with the effective magnetic moment μ eff = 4.14 μ B /Cr-ion and the Weiss constant θ = + 357 K . The low temperature magnetization indicates the spin-wave excitations, where the existence of first term of Bloch T 3/2 law and the next T 5/2 term are verified experimentally. This spin-wave excitation is detected up to approximately 250 K which is a fairly high temperature.