Resonantly enhanced spin-lattice relaxation of Mn2+ ions in diluted magnetic (Zn,Mn)Se/(Zn,Be) Se quantum wells

The dynamics of spin-lattice relaxation in the magnetic Mn2+ ion system of (Zn,Mn)Se/(Zn,Be) Se quantum-well structures are studied using optical methods. Pronounced cusps are found in the giant Zeeman shift of the quantum-well exciton photoluminescence at specific magnetic fields below 10 T, when the Mn spin system is heated by photogenerated carriers. The spin-lattice relaxation time of the Mn ions is resonantly accelerated at the cusp magnetic fields. Our theoretical analysis demonstrates that a cusp occurs at a spin-level mixing of single Mn2+ ions and a quick-relaxing cluster of nearest-neighbor Mn ions, which can be described as intrinsic cross-relaxation resonance within the Mn spin system.