Keshab R. Sapkota

Synthesis and characterization of Co2FeAl nanowires

We report the growth and characterization of Co2FeAl nanowires. Nanowires are grown using electrospinning method and the diameters range from 50 to 500 nm. These nanowires exhibit cubic crystal structure with a lattice constant of a=5.639 A. The nanowires exhibit ferromagnetic behavior with a very high Curie temperature. The temperature dependent magnetization behavior displays an anomaly in the temperature range 600–850 K, which disappears at higher external magnetic fields.We report the growth and characterization of Co2FeAl nanowires. Nanowires are grown using electrospinning method and the diameters range from 50 to 500 nm. These nanowires exhibit cubic crystal structure with a lattice constant of a=5.639 A. The nanowires exhibit ferromagnetic behavior with a very high Curie temperature. The temperature dependent magnetization behavior displays an anomaly in the temperature range 600–850 K, which disappears at higher external magnetic fields.

Electrical and Magnetic Properties of Higher Manganese Silicide Nanostructures

Higher manganese silicide, Mn15Si26, nanostructures were grown using CVD using a coordination compound precursor. These nanostructures exhibit p-type semiconducting behavior. They also exhibit a nonzero magnetic moment even at room temperature and the magnetic transition temperature appears to be near 330 K.

Ni2.36Mn0.72Ga0.92 nanowires with high martensite transition temperature

Nanowires of ferromagnetic shape memory alloy Ni2.36Mn0.72Ga0.92 are grown and their structural and magnetic properties are investigated. Single phase nanowires are obtained only after they were quenched to 77 K from high temperature annealing at 873 K. The nanowires are in martensitic orthorhombic phase and they retain the martensitic nature to low temperature. The martensite phase of the nanowires is supported by magnetic measurements, which showed no anomaly in magnetization versus temperature plot below 400 K. The ferromagnetic transition temperature of the nanowires is observed to be greater than 400 K.

Ferromagnetic, spin glass, and antiferromagnetic behaviors in Cd1−xMnxTe nanowires

The Cd1−xMnxTe (x = 0–0.18) nanowires were grown using a wet-chemical synthesis. The synthesized Cd1−xMnxTe nanowires have diameters in the range of 50–100 nm and display zinc-blend crystal structure. In bulk, Cd1−xMnxTe is extensively studied, but the difficulty in doping Mn in CdTe nanowires delayed the understanding of the properties at the nanoscale. The authors have used a cation exchange method to incorporate Mn in CdTe nanowires. Their magnetic behavior can be tuned by varying the concentration of Mn ions. The CdTe nanowires were paramagnetic while doping small amount of Mn ions introduces ferromagnetic behavior at low temperatures. As the manganese concentration is increased in CdTe, both spin glass and antiferromagnetic behaviors are observed. This is in contrast to what is observed in bulk, where only paramagnetic behavior is observed for x < 0.17.The Cd1−xMnxTe (x = 0–0.18) nanowires were grown using a wet-chemical synthesis. The synthesized Cd1−xMnxTe nanowires have diameters in the range of 50–100 nm and display zinc-blend crystal structure. In bulk, Cd1−xMnxTe is extensively studied, but the difficulty in doping Mn in CdTe nanowires delayed the understanding of the properties at the nanoscale. The authors have used a cation exchange method to incorporate Mn in CdTe nanowires. Their magnetic behavior can be tuned by varying the concentration of Mn ions. The CdTe nanowires were paramagnetic while doping small amount of Mn ions introduces ferromagnetic behavior at low temperatures. As the manganese concentration is increased in CdTe, both spin glass and antiferromagnetic behaviors are observed. This is in contrast to what is observed in bulk, where only paramagnetic behavior is observed for x < 0.17.