Magnetic properties of CuCrZrSe4

We report on structural and magnetic properties of the spinel compound CuCrZrSe4. Rietveld refinement of the powder x-ray diffraction patterns reveals the normal spinel structure AB2Se4, where the Zr4+ and Cr3+ ions occupy the B sites, while the Cu1+ ions are located on A sites. The magnetic susceptibility reveals a Curie–Weiss law above 250 K with a ferromagnetic Curie–Weiss temperature θp=115K and an effective paramagnetic moment μeff=3.75μBμeff=3.75μB per Cr3+ ion corresponding to a g value g=1.94 in fair agreement with electron spin resonance (ESR) measurements. Below 100 K the magnetization deviates from the Curie–Weiss behaviour and splits into field-cooled (FC) and zero-field-cooled (ZFC) branches. A second anomaly in the magnetization close to 10 K, which is also visible in the ESR parameters, indicates the transition into a spin-glass state due to the random distribution of Zr and Cr ions on the B site. This is supported by the frequency dependence of the anomaly detected by AC susceptibility measurements.