Journal of Solid State Chemistry Ferromagnetic phase transition in the spinel-type CuCr2Te4

Ferromagnetic phase transition in spinel-type CuCr2Te4 has been clearly observed. CuCr2Te4 is a telluride-spinel with the lattice constant a = 11.134 Å, which has been synthesized successfully. The heat capacity exhib-its a sharp peak due to the ferromagnetic phase transition with the Cu-rie temperature Tc = 326 K. This value of Tc corresponds exactly to that of the negative peak of dM/dT in low field of 1.0 Oe. The magnetic suscepti-bility shows the Curie-Weiss behavior between 380 and 650 K with the ef-fective magnetic moment µeff = 4.14 µB per Cr-ion and the Weiss constant Ө = 357 K. The low temperature magnetization indicates the spin-wave excita-tions, 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 fairly high temperature