Growth and characterization of GaDyN/GaN double barrierstructures

GaDyN/GaN double-barrier magnetic tunneling junctions (DB-MTJs) structures are grown on GaN templates by radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE). X-ray diffraction (XRD) θ/2θ scan curves exhibited a clear peak of GaDyN at low angle side of the GaN (0002) diffraction peak. From analyzing extended x-ray absorption fine structure (EXAFS), majority of Dy atoms are found to be incorporated into substituting the Ga sites in GaN with wurtzite structure, and GaDyN has longer bond length than that of GaN. From XRD and EXAFS results, the lattice constant of the GaDyN is larger than that of GaN due to large radius of Dy ion. Photoluminescence from GaDyN DB-MTJs structure was found, which is related to the Dy ions. Ferromagnetism is confirmed in the magnetization versus magnetic field curves at room temperature for the all samples. It is found that the magnetization per unit volume and the coercivity show change with increasing the thickness of the middle GaDyN layer. This implies that the interlayer interaction exists between the GaDyN layers. ► GaDyN/GaN double-barrier magnetic tunneling junctions (DB-MTJs) structures are grown by the MBE method. ► Ferromagnetism is confirmed at room temperature for the GaDyN quantum wells. ► It is found that the interlayer interaction exists between the GaDyN quantumwells.