Ferromagnetic Mn-Implanted GaP: Microstructures vs Magnetic Properties

Abstract

Ferromagnetic GaMnP layers were prepared by ion implantation and pulsed laser annealing (PLA). We present a systematic investigation on the evolution of microstructure and magnetic properties depending on the pulsed laser annealing energy. The sample microstructure was analyzed by high-resolution X-ray diffraction (HR-XRD), transmission electron microscopy (TEM), Rutherford backscattering spectrometry (RBS), ultraviolet Raman spectroscopy (UV-RS), and extended X-ray absorption fine structure (EXAFS) spectroscopy. The presence of X-ray Pendellösung fringes around GaP (004) and RBS channeling prove the epitaxial structure of the GaMnP layer annealed at the optimized laser energy density (0.40 J/cm(2)). However, a forbidden TO vibrational mode of GaP appears and increases with annealing energy, suggesting the formation of defective domains inside the layer. These domains mainly appear in the sample surface region and extend to almost the whole layer with increasing annealing energy. The reduction of the Curie temperature (TC) and of the uniaxial magnetic anisotropy gradually happens when more defects and the domains appear as increasing the annealing energy density. This fact univocally points to the decisive role of the PLA parameters on the resulting magnetic characteristics in the processed layers, which eventually determine the magnetic (or spintronics) figure of merit.

Interplay between localization and magnetism in (Ga,Mn)As and (In,Mn)As

“…According to the stopping and range of ions in matter (SRIM) simulation, the longitudinal straggling (∆R P ) for the Mn distribution in GaAs and InAs is around 31 and 38 nm, respectively. A Coherent XeCl laser (with 308 nm wavelength and 28 ns pulse duration) was employed to recrystallize the samples, and the energy densities were optimized to achieve both the highest crystalline quality and the best randomization of the Mn distribution: 0.3 J/cm 2 for (Ga,Mn)As and 0.2 J/cm 2 for (In,Mn)As [24]. Mn concentration profiles were determined by secondary ions mass spectrometry (SIMS) technique using Cameca IMS 6F microanalyser.…”

Hole compensation effect in III-Mn-V dilute ferromagnetic semiconductors

“…GaP exhibits a band gap of 2.26 eV which is larger than the gap of GaAs (1.4 eV) and InAs (0.35 eV), therefore it reveals different features when it is doped with Mn. To date, high-quality epitaxial (Ga,Mn)P thin film can be only obtained by ion implantation combined with pulsed laser melting [27,[29][30][31]. Unexpectedly, even though TC approaches 60 K, the sample is still electrically insulating and the Mn impurity stays separated from the GaP valence band [29][30][31].…”

“…A XeCl excimer pulsed laser (Coherent ComPexPRO201, wavelength λ = 308 nm and pulse duration τ = 30 ns) was used to recrystallize the amorphous as-implanted layers. Different energy densities were used to get the optimal epitaxial structure and the highest Curie temperature for different films, which is 0.20 and 0.40 J/cm 2 for (In,Mn)As and (Ga,Mn)P, respectively [26,27].…”

p -type codoping effect in (Ga,Mn)As: Mn lattice location versus magnetic properties

“…A commercial XeCl pulsed excimer laser (Coherent ComPexPRO201, wavelength λ = 308 nm and pulse duration t = 30 ns) was used for the PLM treatment which was carried out after the successive implantations of Mn and Zn ions. The energy density of 0.3 J/cm 2 was adopted to get the best epitaxial structure as previously reported [19]. It is worth noting that such an ultrafast pulsed laser annealing causes a non-equilibrium recrystallization, which is different from the equilibrium annealing before [20].…”