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The emergence of thin film CoFeB has driven research and industrial applications in the past decades, with the magnetic random access memory (MRAM) the most prominent example. Because of its beneficial properties, it fulfills multiple functionalities as information-storing, spin-filtering, and reference layer in magnetic tunnel junctions. In future, this versatility can be exploited beyond the traditional applications of spintronics by combining with advanced materials, such as oxide-based materials. Pulsed laser deposition (PLD) is their predominant growth-method, and thus the compatibility of CoFeB with this growth technique will be tested here. This encompasses a comprehensive investigation of the structural and magnetic propoperties. In particular, we find a substantial ‘dead’ magnetic layer and confirm that it is caused by oxidation employing the x-ray magnetic circular dichroism (XMCD) effect. The low damping encountered in vector network analyzer-based ferromagnetic resonance (VNA-FMR) renders them suitable for magnonics applications. These findings demonstrate that CoFeB thin films are compatible with emergent, PLD-grown materials, ensuring their relevance for future applications.

Thin-film structures consisting of alternating nanoscale multilayers show substantial hardness increases compared with monolithic coatings of the constituent materials. Coatings, such as TiAlN/VN are deposited using PVD with individual coating bi-layer thickness of ~3nm. Since TiAlN and VN are isostructural and mutually soluble, mixing of the two layers during deposition is expected, which will inevitably affect properties. Energy filtered TEM using a field emission gun source allowed important information on layer structure, but failed to reveal details 600°C, a duplex oxide structure was formed, with several phases observed, including V2O5, TiO2 and AlVO4, with V2O5 being the dominant oxide at the outer layer at 638°C. These coatings exhibit low friction in dry sliding which is believed to arise from the inherently low friction of V2O5. Focused ion beam studies of wear tests at 630°C confirmed that the contact surface comprised small (~50nm), equiaxed and largely agglomerated V2O5 crystals, confirming the hypothesis.

The Young's modulus of 6H single crystal silicon carbide (SiC) was tested with micro cantilevers that had a range of cross-sectional dimensions with surfaces cleaned under different accelerating voltages of Ga+ beam. A clear size effect is seen with Young's modulus decreasing as the cross-sectional area reduces. One of the possible reasons for such size effect is the Ga+ induced damage on all surfaces of the cantilever. Transmission electron microscopy (TEM) was used to analyse the degree of damage, and the measurements of damage is compared to predictions by SRIM irradiation simulation.

TiAlN/VN multilayer coatings exhibit excellent dry sliding wear resistance and low friction coefficient, believed to be associated with the formation of tribo-films comprising Magnéli phases such as V2O5. In order to investigate this hypothesis, dry sliding wear of TiAlN/VN coatings was undertaken against Al2O3. Focused ion beam was used to generate site-specific TEM specimens. A thin (2-20nm) tribo-film was observed at the worn surface, with occasional 'roll-like' wear debris (φ 5-40nm). Both were amorphous and contained the same Ti, Al and V ratio as the coating, but with the nitrogen largely replaced by oxygen. No evidence of Magnéli phases was found. © 2006 IOP Publishing Ltd.

Nitride based protective coatings produced by physical vapour deposition offer a promising means to extend the oxidation and wear performance of γ-TiAl. Metal ion pre-etching of the substrate surface has been shown to significantly enhance the adhesion between the coating and substrate. In this study we have applied spectroscopic imaging and advanced STEM analysis to study such interfaces. For a conventional Cr cathodic arc discharge Cr ion implantation of ~6nm into the substrate was observed. For an etch using high power impulse magnetron sputtering the metal ion implantation depth was reduced to ~2-3nm. In both cases a corresponding depletion zone of Ti and Al was observed. In addition, nitrogen diffusion into the substrate during coating deposition was also revealed to a similar depth respectively.

There is a major drive to introduce γ-TiAl into gas turbine engines in order to reduce weight. However, this will require the development of coatings that protect against oxidation at high temperature, but do not adversely affect the mechanical properties. This work reports the high temperature degradation mechanisms of a nanoscale CrAlYN/CrN multilayer coating deposited on γ-TiAl(8Nb) by a combined high power impulse magnetron sputtering / unbalanced magnetron sputtering. Detailed TEM/STEM of FIB prepared specimens from isothermal static oxidation tests at 850°C for up to 1030 hours is presented. The evolution of the complex oxide structure and the implications for future coating development is discussed.