Abstract
In (Ga,Mn)As, a model dilute magnetic semiconductor, the electric and magnetic properties are strongly influenced by the lattice sites occupied by the Mn atoms. In particular, the highest Curie temperatures are achieved upon thermal annealing in a narrow temperature window around $200{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$, by promoting the diffusion of interstitial Mn towards the surface. In this work, we determined the thermal stability of both interstitial and substitutional Mn in ferromagnetic (Ga,Mn)As thin films, using the emission channeling technique. At a higher Mn concentration, the temperatures at which substitutional and interstitial Mn become mobile not only decrease, but also become closer to each other. These findings advance our understanding of self-compensation in (Ga,Mn)As by showing that the strong dependence of the Curie temperature on annealing temperature around $200{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ is a consequence of balance between diffusion of interstitial Mn and segregation of substitutional Mn.
Highlights
(Ga,Mn atoms (Mns))As, a dilute magnetic semiconductor (DMS), is a model system for studying carrier-mediated ferromagnetism in semiconductors and the associated spintronic phenomena [1,2,3]
Emission channeling results are presented and discussed in two parts starting with the identification of which lattice sites Mn occupies in (Ga,Mn)As
This analysis includes a model for the diffusion of both Mns and Mni, as well as a discussion of its implications on the understanding of Mn thermal stability in (Ga,Mn)As
Summary
(Ga,Mn)As, a dilute magnetic semiconductor (DMS), is a model system for studying carrier-mediated ferromagnetism in semiconductors and the associated spintronic phenomena [1,2,3]. Previous studies on (Ga,Mn)As have focused on a careful optimization of the synthesis and postgrowth treatments, aiming to improve two key properties: the Curie temperature (TC) and the magnetization [4,5,6,7,8] In these studies at high Mn concentration (several percent), interstitial Mn was found to out-diffuse during thermal annealing in the 160–200 ◦C temperature range [7,8,9,10]. Using the emission channeling technique, we observe that, with increasing Mn concentration, the temperatures at which Mns and Mni become mobile decrease, and become closer to each other These results show that the narrow annealing temperature window in which the TC and magnetization can be optimized in (Ga,Mn)As results from a fine balance between diffusion of Mni and segregation of Mns
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
