Magnetism of Magnetic Impurity Doped GaN Modulated by Spinodal Decomposition

GaN is expected as a material of full-color monolithic light emitting diodes (LEDs), because GaN and InGaN are known as materials of blue and green LEDs, respectively and Eu-doped GaN enabled to fabricate red LEDs. Eu-doped GaN possesses not only an ability to emit light but also magnetic properties and self-generated modulations by spinodal decomposition. This property provides us with an expectation of fabrication of multifunctional materials for spintronics. We investigate magnetism of magnetic Eu-doped GaN modulated by spinodal decomposition using the density functional calculations and the Monte-Carlo simulations. As a result, we obtain that the larger cluster of EuN causes hystereses of magnetization as a function of external magnetic field. In this talk, we will discuss the magnetism, the critical temperatures, and an effect of the magneto-crystalline anisotropies.