High-temperature ferromagnetism in new n-type Fe-doped ferromagnetic semiconductor (In,Fe)Sb

Abstract

Over the past two decades, intensive studies on various ferromagnetic semiconductor (FMS) materials have failed to realize reliable FMSs that have a high Curie temperature (TC > 300 K), good compatibility with semiconductor electronics, and characteristics superior to those of their nonmagnetic host semiconductors. Here, we demonstrate a new n-type Fe-doped narrow-gap III–V FMS, (In1−x,Fex)Sb. Its TC is unexpectedly high, reaching ∼335 K at a modest Fe concentration (x) of 16%. The anomalous Hall effect and magnetic circular dichroism (MCD) spectroscopy indicate that the high-temperature ferromagnetism in (In,Fe)Sb thin films is intrinsic and originates from the zinc-blende (In,Fe)Sb alloy semiconductor.

Hybridization between the ligand p band and Fe−3d orbitals in the p-type ferromagnetic semiconductor (Ga,Fe)Sb

“…Since the doped Fe ions are expected to isovalently substitute for the cation (In 3+ or Ga 3+ ) sites of III-V semiconductors as Fe 3+ , one can independently control the concentrations of Fe ions and, by doping other atoms, carriers in Fe-doped FMSs. Furthermore, the previously reported highest TC values n-type (In0.84,Fe0.16)Sb (335 K) 16 , (In0.65,Fe0.35)Sb (385 K) 17 , and p-type (Ga0.8,Fe0.2)Sb (> 400 K) 18 are well above room temperature. Considering these advantages, Fe-based FMSs are more promising materials for applications to semiconductor spintronic devices operating at room temperature.…”

A substantial increase of Curie temperature in a new type of diluted magnetic semiconductors via effects of chemical pressure

“…The advantage leads to potential applications in spintronic devices. [1][2][3] Specifically, recently couples of Fe-doped III-V DMS reached relatively high Curie temperature (T C ~ 320-340 K), [4][5][6] which challenges existing concepts and motivates further understanding of ferromagnetism in DMS. The spin & charge doping are induced by one element doping such as Mn doping into (Ga,Mn)As leading to difficulty in tuning either conducting or magnetic properties.…”

Heavily Fe-doped n-type ferromagnetic semiconductor (In, Fe)Sb with high Curie temperature and large magnetic anisotropy

“…semiconductor InSb, as in the case of many other FMSs. 27,28,10 Note that such local fluctuation of Fe concentration has been reported in the (In,Fe)Sb sample x = 16%, 16 thus it is not surprising to observe this behavior in the samples with x = 20 -35%. (black circles).…”

“…(black circles). 16 One can see that T C increased from 335 K at x = 16% 16 to 390 K at x = 35%, which is far above room temperature (300 K), and thus promising for realistic devices operating at room temperature. The reason why T C slowly increases in the range of x = 20 -35% is unclear at the present.…”

“…Since Fe atoms replacing group III cation sites are in the neutral state (Fe 3+ ) in III-V semiconductors, we are able grow both p-type (Ga,Fe)Sb [9][10][11] , insulating (lightly p-type) (Al,Fe)Sb 12 , n-type (In,Fe)As [13][14][15] and (In,Fe)Sb. 16,17 We have recently obtained T C = 340 K in (Ga 1-x ,Fe x )Sb with x = 25% 11 and T C = 335 K in (In 1-x ,Fe x )Sb with x = 16%, 16 which are the highest T C values reported in III-V FMSs so far. However, Fe-doped FMSs lack large magnetic anisotropy, thus they have small remanent magnetization and small coercive force, which are inappropriate for device applications.…”