Large magneto-optical effect in low-temperature-grown GaCrN and GaCrN:Si

GaCrN layers were grown at 300 and 100 °C by radio‐frequency plasma‐assisted molecular‐beam epitaxy on sapphire substrates. X‐ray diffraction results showed no obvious secondary phase in the GaCrN samples grown at 300 °C with Cr concentration even up to 9%. A very sharp line was found at 356 nm in the photoluminescence spectra below 50 K, which comes from high crystalline quality regions in the GaCrN layers. All the samples grown at low temperatures exhibited ferromagnetic characteristics. Si‐doped GaCrN with Cr concentration of 6% has the largest saturation magnetization. Magnetic circular dichroism (MCD) measurement was performed for these samples at 10 K to investigate magneto‐optical effect. Large magneto‐optical effect was confirmed in the low‐temperature‐grown non‐doped and Si‐doped GaCrN. Zeeman splitting was enhanced by Si‐doping in the low‐temperature‐grown GaCrN (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)