EPR Spectra of Sintered Cd 1-x Cr x Te Powdered Crystals with Various Cr Content

Materials (Basel). 2021 Jun 22;14(13):3449. doi: 10.3390/ma14133449.

Abstract

In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1-xCrxTe (0.002 < x < 0.08) were measured with a dependence on temperature (82 K < T < 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie-Weiss law and the paramagnetic Curie temperature was obtained.

Keywords: CdTe:Cr; Curie temperature; diluted magnetic semiconductors; electron paramagnetic resonance; ferromagnetic materials.