Enhanced magnetic anisotropy and high hole mobility in magnetic semiconductor Ga1-x-y Fe x Ni y Sb

Abstract

(Ga,Fe)Sb is a promising magnetic semiconductor (MS) for spintronic applications because its Curie temperature (T _C) is above 300 K when the Fe concentration is higher than 20%. However, the anisotropy constant K _u of (Ga,Fe)Sb is below 7.6 × 10³ erg/cm³ when Fe concentration is lower than 30%, which is one order of magnitude lower than that of (Ga,Mn)As. To address this issue, we grew Ga_1-x-y Fe _x Ni _y Sb films with almost the same x (≈24%) and different y to characterize their magnetic and electrical transport properties. We found that the magnetic anisotropy of Ga_0.76-y Fe_0.24Ni _y Sb can be enhanced by increasing y, in which K _u is negligible at y = 1.7% but increases to 3.8 × 10⁵ erg/cm³ at y = 6.1% (T _C = 354 K). In addition, the hole mobility (µ) of Ga_1-x-y Fe _x Ni _y Sb reaches 31.3 cm²/(V∙s) at x = 23.7%, y = 1.7% (T _C = 319 K), which is much higher than the mobility of Ga_1-x Fe _x Sb at x = 25.2% (µ = 6.2 cm²/(V∙s)). Our results provide useful information for enhancing the magnetic anisotropy and hole mobility of (Ga,Fe)Sb by using Ni co-doping.