Applied

From experimental to natural granular flows

By Dean Williams on March 9, 2017

Can small scale experiments help to understand and quantify granular flows at the geophysical scale?

Fig. 1. Magnetic cooling principle demonstrated in terms of the spin and phonon systems of a solid. The application of the magnetic field leads to the alignment of spins and reduces the magnetic entropy Smag. Under adiabatic conditions (the total entropy is constant), the reduction in the magnetic entropy is compensated by an increase in the phonon part of the entropy Sph, i.e. by intensified lattice vibration (see a largely exaggerated phonon wave in step I). As a result of the increased lattice vibration the temperature rises. The evolved heat is removed from the system to the environment (step II). On thermal isolation of the solid from the environment and removal of the magnetic field, the spins randomise causing an increase in Smag and the corresponding reduction in Sph (step III). This step leading to the temperature reduction forms the basis of the magnetic cooling. Image taken from Julia Lyubina 2017 J. Phys. D: Appl. Phys. 50 053002, © IOP Publishing, All Rights Reserved.

Magnetic cooling: how cool is that!

By Dean Williams on February 17, 2017

More than 15 % of energy is spent worldwide on various forms of cooling. In addition to the energy bill, the compressor in cooling units can bring a rich palette of sounds to your home: think of all this clanking,… Read More ›

A typical spectral map with a set of lines of spectra for exchange spin waves, both in coordinates kAa, kBa. Image taken from V V Kruglyak et al 2017 J. Phys. D: Appl. Phys. 50 094003, © IOP Publishing, All Rights Reserved.

Image of the Week: A spectral map for exchange spin waves

By Dean Williams on February 6, 2017

This week’s image of the week is a typical spectral map with a set of lines of spectra for exchange spin waves, both in coordinates kAa, kBa. The image is taken from the article “Formation of the band spectrum of… Read More ›

Computer simulations showing the complex motion of a domain wall as it is driven through a Ni80Fe20 nanowire by an applied magnetic field. The black arrows indicate the direction of the magnetisation in the two magnetic domains the domain wall separates, while the colour contrast indicates the local direction of the magnetisation at each point in the nanowire. Image taken from T J Hayward and K A Omari 2017 J. Phys. D: Appl. Phys. 50 084006, © IOP Publishing, All Rights Reserved.

Understanding Delinquent Domain Walls

By Dean Williams on February 1, 2017

Why do apparently simple nanomagnets exhibit such complicated behaviours?

Emergent elemental two-dimensional materials: an interview with leading scientist Guy Le Lay

By Tom Miller on January 25, 2017

Journal of Physics D: Applied Physics recently published a fascinating Topical Review by leading 2D materials scientist, Guy Le Lay (Aix-Marseille Université). Guy and his co-authors focus on new elemental 2D materials such as silicene, phosphorene, germanene and stanene, discussing… Read More ›

PTW preparations with various atmospheric and dissolved gas species in DW. PTW was prepared by discharging the LF plasma jet in the presence of controlled atmospheric and dissolved gases. O2- adduct-forming potential and bactericidal activity of PTW were measured. (A) Signal intensity of the O2- adduct, as determined by ESR. (B) Bactericidal activity against E. coli. Helium, nitrogen, oxygen, and synthetic air were used as atmospheric and dissolved gases; bactericidal activity was evaluated by MIC. Image taken from Satoshi Ikawa et al 2016 J. Phys. D: Appl. Phys. 49 425401. IOP Publishing, All Rights Reserved.

Bactericidal plasma-treated water formed with nitrogen

By Dean Williams on October 4, 2016

Peroxynitric acid formed in water by plasma exposure is a key molecule for bactericidal effect.

Figure 1: Formation energy of metal (left panels) and N (right panels) vacancies in c-MoN (upper panels) and c-TaN (lower panels), as a function of vacancy concentration and the degree of order characterised by a parameter α (for detailed explanation please see our paper). Image taken from Nikola Koutná et al 2016 J. Phys. D: Appl. Phys. 49 375303, © IOP Publishing, All Rights Reserved.

Point defects stabilise cubic Mo-N and Ta-N

By Dean Williams on September 6, 2016

Does ordering of vacancies and their type play any role on stability of MoN and TaN?

Tilted-view SEM images of a GaN/InGaN microdisk with radius of 3.5 µm. (a) Before KOH wet-etch and on Si pedestals with radii of (b) 1.75 µm, (c) 1.05 µm and (d) 0.35 µm. The scale bars represent 2 µm. Image taken from Yiyun Zhang et al 2016 J. Phys. D: Appl. Phys. 49 375103. © IOP Publishing, All Rights Reserved.

Image of the Week: GaN/InGaN microdisks, or “micromushrooms”

By Dean Williams on August 30, 2016

This week’s image of the week is taken from a recent paper in Journal of Physics D: Applied Physics from researchers at the University of Hong Kong, Nanjing University of Posts and Telecommunications and the University of Sheffield. The image… Read More ›