Intrinsic or Interface Clustering-Induced Ferromagnetism in Fe-Doped In₂O₃-Diluted Magnetic Semiconductors

Abstract

Five percent Fe-doped InO films were deposited using a pulsed laser deposition system. X-ray diffraction and transmission electron microscopy analysis show that the films deposited under oxygen partial pressures of 10 and 10 Torr are uniform without clusters or secondary phases. However, the film deposited under 10 Torr has a Fe-rich phase at the interface. Magnetic measurements demonstrate that the magnetization of the films increases with decreasing oxygen partial pressure. Muon spin relaxation (μSR) analysis indicates that the volume fractions of the ferromagnetic phases in PO = 10, 10, and 10 Torr-deposited samples are 23, 49, and 68%, respectively, suggesting that clusters or secondary phases may not be the origin of the ferromagnetism and that the ferromagnetism is not carrier-mediated. We propose that the formation of magnetic bound polarons is the origin of the ferromagnetism. In addition, both μSR and polarized neutron scattering demonstrate that the Fe-rich phase at the interface has a lower magnetization compared to the uniformly distributed phases.

Hybrid Ni–Boron Nitride Nanotube Magnetic Semiconductor—A New Material for Spintronics

“…Figure 9a also shows that the magnitude of magnetization has increased with decreasing the temperature for the FC curve and reached the magnetization value of 0.26 emu/g at 5 K, and for the ZFC curve, magnetization has decreased with decrease in temperature and reached the magnetization value of 0.21 emu/g at 5 K. Thus, the temperature-dependent magnetization ZFC and FC clearly show a weak ferromagnetic behavior from room temperature to low temperature. The isothermal magnetization of BNNTs measured at various temperatures (5,10,20,30,40,50,100,150,200,250, and 300 K) in the applied magnetic field of 2 T is shown in Figure 9b, and here, it does not show hysteresis loops and the value of saturation increased sharply with increasing the magnetic field strength for the nanotubes. Isothermal magnetization of the nanotubes shows weak ferromagnetic nature for all temperatures, and the magnitude of saturation magnetization has increased with decreasing temperature with respect to the magnetic field of 2 T, as shown in Figure 10b.…”

“…These combined magnetic and semiconducting properties could be highly useful in spintronic devices. 9 , 10 Spintronics is the study of transport phenomena which depend on the electron spin. 11 The presence of ferromagnetism and semiconductivity in a single material is highly sought after.…”

“…Only in the late eighties, the presence of magnetism in semiconductors was discovered when the semiconductor was doped with transition metals; materials which exhibited both magnetic and semiconducting properties were known as magnetic semiconductors. These combined magnetic and semiconducting properties could be highly useful in spintronic devices. , Spintronics is the study of transport phenomena which depend on the electron spin . The presence of ferromagnetism and semiconductivity in a single material is highly sought after.…”

Nano-Structured Dilute Magnetic Semiconductors for Efficient Spintronics at Room Temperature

“…A mesoporous In2O3 semiconductor implanted with Co ions shows a measurable ferromagnetic signature at RT [111]. Co-doped In2O3 synthesized by chemical solution route showed FM at RT and Some other methods, such as 5% Fe-doped In 2 O 3 films which were pulsed laser deposited under a partial pressure of 10 −3 , 10 −5 and 10 −7 torr, respectively [107] and polarized neutron scattering measurements reveal lower magnetized Fe-rich phase located at the interface than uniformly distributed phases. A similar study was reported by Garnet et al showing ferromagnetic ordering with decreased saturation magnetization with concentration for Fe in In 2 O 3 nanocrystalline films prepared by the sol-gel method [108].…”

Activation and Enhancement of Room-Temperature Ferromagnetic Exchange in (Cu,N)-codoped In2O3 Dilute Magnetic Nanowires

“…In recent years, diluted magnetic oxides (DMOs) by manipulating the charge and spin of electron have drawn immense attention because of their possible applications in spin-dependent multifunctional devices. − Ideal DMO materials require having the Curie temperature ( T C ) above room temperature (RT), high spin polarization, and intrinsic ferromagnetism. Because theoretical prediction based on the Zener models opens a window for achieving RT ferromagnetic ordering in oxide semiconductors with a wide band gap, transition metal (TM)-doped ZnO, TiO 2 , SnO 2 , and In 2 O 3 have been widely investigated. − Indium oxide (In 2 O 3 ) is a very important wide-band gap (3.75 eV) n-type semiconductor and has been considered as a promising candidate for DMOs owing to good conductivity and high chemical stability. , Recently, different research groups have reported that RT ferromagnetism can be obtained in In 2 O 3 -doped with Fe, Mn, Co, Ni, and so forth. − However, similar systems exhibit quiet conflicting magnetic characters, such as paramagnetic, nonmagnetic, and magnetic characters. − The origin of the observed RT ferromagnetism is still highly controversial. The different magnetic mechanisms in DMOs, such as RKKY exchange interaction, double exchange interaction, as well as bound magnetic polaron (BMP) model-based point defects, have been proposed for TM-doped In 2 O 3 in previous reports. , The nanosized TM precipitates in the In 2 O 3 host may also induce ferromagnetism, which is undesirable for practical applications.…”