Effect of epitaxy and lattice mismatch on saturation magnetization of γ′-Fe4N thin films

2008 ◽  
Vol 92 (22) ◽  
pp. 222507 ◽  
Author(s):  
Shahid Atiq ◽  
Hyun-Seok Ko ◽  
Saadat Anwar Siddiqi ◽  
Sung-Chul Shin
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.


Author(s):  
Karren L. More

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.


2013 ◽  
Vol 690-693 ◽  
pp. 1702-1706 ◽  
Author(s):  
Shuang Jun Nie ◽  
Hao Geng ◽  
Jun Bao Wang ◽  
Lai Sen Wang ◽  
Zhen Wei Wang ◽  
...  

NiZn-ferrite thin films were deposited onto silicon and glass substrates by radio frequency magnetron sputtering at room temperature. The effects of the relative oxygen flow ratio on the structure and magnetic properties of the thin films were investigated. The study results reveal that the films deposited under higher relative oxygen flow ratio show a better crystallinity. Static magnetic measurement results indicated that the saturation magnetization of the films was greatly affected by the crystallinity, grain dimension, and cation distribution in the NiZn-ferrite films. The NiZn-ferrite thin films with a maximum saturation magnetization of 151 emucm-3, which is about 40% of the bulk NiZn ferrite, was obtained under relative oxygen flow ratio of 60%.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chokkakula L. P. Pavithra ◽  
Reddy Kunda Siri Kiran Janardhana ◽  
Kolan Madhav Reddy ◽  
Chandrasekhar Murapaka ◽  
Joydip Joardar ◽  
...  

AbstractDiscovery of advanced soft-magnetic high entropy alloy (HEA) thin films are highly pursued to obtain unidentified functional materials. The figure of merit in current nanocrystalline HEA thin films relies in integration of a simple single-step electrochemical approach with a complex HEA system containing multiple elements with dissimilar crystal structures and large variation of melting points. A new family of Cobalt–Copper–Iron–Nickel–Zinc (Co–Cu–Fe–Ni–Zn) HEA thin films are prepared through pulse electrodeposition in aqueous medium, hosts nanocrystalline features in the range of ~ 5–20 nm having FCC and BCC dual phases. The fabricated Co–Cu–Fe–Ni–Zn HEA thin films exhibited high saturation magnetization value of ~ 82 emu/g, relatively low coercivity value of 19.5 Oe and remanent magnetization of 1.17%. Irrespective of the alloying of diamagnetic Zn and Cu with ferromagnetic Fe, Co, Ni elements, the HEA thin film has resulted in relatively high saturation magnetization which can provide useful insights for its potential unexplored applications.


1995 ◽  
Vol 401 ◽  
Author(s):  
L. Ryen ◽  
E. Olssoni ◽  
L. D. Madsen ◽  
C. N. L. Johnson ◽  
X. Wang ◽  
...  

AbstractEpitaxial single layer (001) SrTiO3 films and an epitaxial Yba2Cu3O7-x/SrTiO3 multilayer were dc and rf sputtered on (110)rhombohedral LaAIO3 substrates. The microstructure of the films was characterised using transmission electron microscopy. The single layer SrTiO3 films exhibited different columnar morphologies. The column boundaries were due to the lattice mismatch between film and substrate. The boundaries were associated with interfacial dislocations at the film/substrate interface, where the dislocations relaxed the strain in the a, b plane. The columns consisted of individual subgrains. These subgrains were misoriented with respect to each other, with different in-plane orientations and different tilts of the (001) planes. The subgrain boundaries were antiphase or tilt boundaries.The individual layers of the Yba2Cu3O7-x/SrTiO3 multilayer were relatively uniform. A distortion of the SrTiO3 unit cell of 0.9% in the ‘001’ direction and a Sr/Ti ratio of 0.62±0.04 was observed, both in correspondence with the single layer SrTiO3 films. Areas with different tilt of the (001)-planes were also present, within each individual SrTiO3 layer.


1999 ◽  
Vol 574 ◽  
Author(s):  
D. Kumar ◽  
K. G. Cho ◽  
Zhang Chen ◽  
V. Craciun ◽  
P. H. Holloway ◽  
...  

AbstractThe growth, structural and cathodoluminescent (CL) properties of europium activated yttrium oxide (Eu:Y2O3) thin films are reported. The Eu:Y2O3 films were grown in-situ using a pulsed laser deposition technique. Our results show that Eu:Y2O3 films can grow epitaxially on (100) LaAlO3 substrates under optimized deposition parameters. The epitaxial growth of Eu:Y2O3 films on LaAlO3, which has a lattice mismatch of ∼ 60 %, is explained by matching of the atom positions in the lattices of the film and the substrate after a rotation. CL data from these films are consistent with highly crystalline Eu:Y2O3 films with an intense CL emission at 611 nm.


1994 ◽  
Vol 339 ◽  
Author(s):  
T. J. Kistenmacher ◽  
S. A. Ecelberger ◽  
W. A. Bryden

ABSTRACTIntroduction of a buffer layer to facilitate heteroepitaxy in thin films of the Group IIIA nitrides has had a tremendous impact on growth morphology and electrical transport. While AIN- and self-seeded growth of GaN has captured the majority of attention, the use of AIN-buffered substrates for InN thin films has also had considerable success. Herein, the properties of InN thin films grown by reactive magnetron sputtering on AIN-buffered (00.1) sapphire and (111) silicon are presented and, in particular, the evolution of the structural and electrical transport properties as a function of buffer layer sputter time (corresponding to thicknesses from ∼50Å to ∼0.64 μm) described. Pertinent results include: (a) for the InN overlayer, structural coherence and homogeneous strain normal to the (00.1) growth plane are highly dependent on the thickness of the AIN-buffer layer; (b) the homogeneous strain in the AIN-buffer layer is virtually nonexistent from a thickness of 200Å (where a significant X-ray intensity for (00.2)AIN is observed); and (c) the n-type electrical mobility for films on AIN-nucleated (00.1) sapphire is independent of AIN-buffer layer thickness, owing to divergent variations in carrier concentration and film resistivity. These effects are in the main interpreted as arising from a competition between the lattice mismatch of the InN overlayer with the substrate and with the AIN-buffer layer.


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