Condensed Matter and Magnetism Research Group

Experimental and theoretical Honours/Masters/PhD students are invited to join the group and work on the projects described below, especially on our flagship projects – Physical Reservoir Computing employing nonlinear spin waves and Magnetic Hydrogen Gas Sensing for Green Energy. Please contact Mikhail if you are interested.

Group Leader

Prof. Mikhail Kostylev

Group Members

Dr. Thomas Schefer

Current HDR students

Shahbaz Khan, Reyne Dowling and Charles Weiss: PhD students

Mohamed Yusuf, Vincent Bochat, Sandesh Regmi: Masters students

Group overview

Our group is well known internationally, and our research papers are well cited by the international Magnetism community. Within the last 10 years, we published 88 research papers; they were cited more than 1300 times.

We collaborate with leading research groups in our area of research from the USA, Germany, France, Italy, Singapore, India and Russia. In the frames of those collaborations, the group hosted masters and PhD students and postdocs from Germany, France, UK, Japan, Switzerland, China and India.

Our students travelled for joint research to Strasburg University and the University Paris Nord (both France), Helmholtz Zentrum Dresden Rossendorf (Germany) and the University of Singapore.

Most of our Honours and Masters graduates either continued to do a PhD with our group, or were admitted into a PhD study abroad (University of Sheffield, UK; Potsdam University, Germany.)

Our PhD graduates got offers of teaching and research positions at the University of Colorado, Colorado- Springs (USA), Newcastle University (UNSW), and postdoctoral positions at UWA, Oxford University (UK), University Paris Sud (France), Stockholm University (Sweden), and high-tech electronics companies from Singapore and the USA. They also found jobs at data-mining and software-development companies from WA and larger Australia. The group’s postdocs have won the prestigious Australian Research Council Distinguished Early-Career Researcher Award (ARC DECRA) and University Post-Doctoral Fellowship (UWA UPRF).

Thomas Schefer in the cleanroom of UWA’s micro-fabrication facility

The Condensed Matter Physics

The Condensed Matter Physics (CMP) is the largest research field in Physics, with 40% of the total research in Physics being generated by the CMP area. Within the last 20 years, 8 Nobel Prizes were awarded for discoveries in CMP, which make 40% of all Nobel Prizes in Physics.
The knowledge generated by CMP represents the foundations of modern electronics and has enabled breakthroughs in other areas of Physics. LEDs, semiconductor lasers, laser amplifiers, optical fibres, high-temperature superconductors, solid-state hard drives, superconducting qubits, integrated optics and optical microchips, etc… are based on discoveries by Condensed-Matter Physicists. Most of these discoveries led to Nobel Prizes. The recent experimental discovery of gravitational waves would not have been possible if CMP physicists had not discovered semiconductor heterostructures used in modern lasers. Quantum computers are based on either the superconductivity effect in metals or optical properties of solids. The accelerators of the Large Hadron Collider uses superconducting electromagnets to steer the particles.

Magnetism

Magnetism is a research area that belongs to Condensed Matter Physics. The modern physical research in this area is focused on behaviour of magnetic objects with characteristic sizes in the nanometre range (1 nanometre (nm) is one millionth of millimetre). These objects may be thin layers (“films”) of magnetic metals or much more complicated advanced chemical compounds, such as single-crystal films of oxides of magnetic-atom species. The characteristic thicknesses of these magnetic films are on the order of 1 nm or below. A Nobel Prize in Physics was awarded for this work in 2007, because of an extreme importance of the research into thin magnetic films for applications. Indeed, the modern cloud information storage would have been hardly possible without the discovery of the magnetic tunnel junction for which the Nobel Prize was awarded.
A large interest also exists for the magnetic behaviour of more complicated objects, having all three dimensional sizes in the nanometre-range. Examples of these are magnetic nanodots and magnetic nanoparticles. Theoretical and experimental research shows that reducing the sizes of magnetic objects to this scale drastically changes their behaviour. Many applications of the magnetic properties of those objects in Electronics and Bio-Medicine have been proposed.

In addition, Magnetism is an effect of quantum nature, and the quantum origins of the effect currently attract more and more researchers with interest in Quantum Information and Quantum Computing to this field. Significant breakthroughs in this area have been achieved recently, and our group has contributed to the breakthroughs (more detail below).

Charles-PF520190611-8-structure overview.tif

Magnetic microstructure to study properties of spin waves. Charles Weiss fabricated it during his visit to Strasbourg University, France. Charles took this electron-microscope image while in Strasbourg. The scale bar in the image is 20 micrometre long. The finest details of the structure have sizes of several hundreds of nanometre.

Our research

The current focus of the Condensed Matter and Magnetism research group is waves and oscillations in solids. Solids support propagation of different waves – sound (phonons), light (photons), light-like excitations called plasmons and waves of magnetic nature called spin waves or magnons. The latter waves exist in magnetic solids. In addition, multiple natural resonances exist in solids, for example plasmonic, electron-spin and ferromagnetic (FMR) resonances. We study these excitations both theoretically and experimentally. Our focus is on magnetic solids.

Theory of spin waves

Spin wave excitations exist in the microwave frequency range (0.5 Gigahertz to 100 Gigahertz). This is the same frequency range, where radios of mobile phones and GPS navigation operate. Therefore, one large area of spin wave research is exploring possibilities of using their properties to build novel microwave signal-processing devices [4,5]. Furthermore, spin waves are also used as way of probing characterise magnetic materials and to extract their magnetic parameters [5]. Exploiting spin waves in those applications requires an important input from theoreticians [4]. Theoreticians are able to predict how spin waves propagate in magnetic nanostructures, how they scatter from natural and artificially introduced non-uniformities of the wave-guiding medium, and how these waves can be excited and detected.
Theoreticians are also interested in spin waves as one of the most nonlinear wave objects known to science. Our group are world-leading experts in the theory of spin waves, and our theoretical papers on that matter are highly cited. Furthermore, we are constantly invited by world-leading experimental groups in the field to provide them with a theoretical explanation of their experimental data. This often requires constructing a new theory based on a theoretical approach that has never been exploited before by the spin-wave community [4]. Our recent theoretical predictions include the use of spin waves in Quantum Information [12] and Quantum Computing [13]. We have also built a theoretical model of the operation of a spin-wave based physical reservoir computer, which is a special type of a neural network.

Quantum Information, Quantum Computing and Artificial Neural networks based on magnons (experiment and theory)

Our recent discoveries include suggestions of using magnons in Quantum Information and Quantum Computing [12,13] and in artificial neural networks. Our latest proposal is a neural network called physical reservoir [6,9], which is based on very exciting Physics of Nonlinear Waves on the one hand. On the other hand, it is based on wave excitations of magnetic nature (magnons) in thin magnetic films. Therefore, we called this concept “Magnonic Reservoir Computer”. who is one of the proposers of this pioneering concept, was offered a postdoc at Oxford University, even before he started writing up his thesis.

Physics of nonlinear waves (theory and experiment)

The concepts of solitons (or solitary waves) is an important result of the physics of nonlinear waves. One example of a solitary wave is the tsunami wave. Theoretically, it is governed by the same equation as a wave in a wave pool. Spin waves in thin magnetic films are one more model medium to study solitary waves and other nonlinear effects, and you can do it on a desktop and without getting wet. Our group has contributed to this field significantly both theoretically and experimentally. One very interesting theoretical result we obtained is shown in the figure to the right.

A 3D visualisation of our theoretical prediction that spin wave bullets collapse via irradiation of caustic waves from them. The large peak in the figure is the spin-wave bullet. It is moving into the page. On its way, it irradiates two narrow beams backwards. The angle of 64 degrees between the beams is very specific and affected by the Doppler Effect, because the bullet speed is very high – about 2.5 km/s. The bullet loses its energy through this process and will eventually die, once it has run out of energy.

Magnetic approaches to Green Energy (experiment)

We have found that magnetism of some magnetic films that contain palladium metal responds strongly to the presence of hydrogen gas in the film environment. Since then we have been studying this interesting physical effect in detail [1,2,8,10,11]. Now this project is sponsored by local WA industry. The ultimate goal of the project is to develop an efficient hydrogen gas sensor for the hydrogen energy sector and eco-friendly automotive industry.

Applications of magnetic nanomaterials in Bio-Medicine
(experiment and numerical modelling)

We also look at the possibility to employ the FMR response of magnetic nanostructures as a physical principle for a sensor of magnetic nanoparticles. The nanoparticles are used in Microbiology and Medicine to detect anti-bodies that are produced by human bodies in response to infectious diseases (e.g. COVID) and tumours. In this way, the problem of diagnosing those conditions can be reduced to detecting nanoparticles introduced into a solution that contains a body liquid, e.g. blood. In our work, we strive to develop a new method of nanoparticle detection that employs magnetic properties of nanoparticles.
In order to efficiently detect a magnetic nanoparticle, the detector must have sizes that are also on the nanometre scale. Our discovery was that magnetic nanostructures called “anti-dots” are excellent candidates for the detectors. Anti-dots represent an array of nanoholes in a continuous magnetic film. We found that the FMR response of these nanomaterials is strongly affected by the tiny magnetic fields the nanoparticles create around them.

An array of holes (anti-dots) drilled in a thin layer of magnetic metal by Reyne Dowling. The hole diameter is about 300 nm. Reyne used a Focused Ion Beam setup at UWA’s Microscopy Centre (CMCA) to drill the holes. The small white objects with irregular shapes in the figure are magnetic nanoparticles captured by the nanostructure. Reyne took this electron microspore image at UWA’s Microscopy Centre (CMCA)

Design, fabrication and characterisation of magnetic materials

We have designed and fabricated a number of advanced magnetic materials. To fabricate them we use the clean room of the WA Node of the Australian National Fabrication Facility that is located on the UWA campus [8]. In addition, we have a magnetron sputtering machine in our lab, and many films and multilayers we fabricated were made with this machine [11].
We use a number of experimental tools available in our lab to characterise these materials and ones fabricated for us by overseas-based collaborators. The tools include several FMR setups, a microscopic microwave probe based setup to investigate the propagation of spin waves on the micron and sub-micron scales, and a Magneto-Optical Kerr Effect setup.
We also employ neutron and X-ray beams to investigate our films. To this end, we travel to the neutron scattering facility of the Australian Nuclear Science and Technology Organisation (ANSTO), located in Sydney. Our group pioneered combining neutron studies with FMR by developing an FMR setup that can operate directly on the neutron beam line [11]. In the photo to the left, Mikhail is loading a magnetic film sample into the sample holder of ANSTO’s Platypus instrument. The sample holder actually represents an FMR fixture that allows taking FMR and polarised-neutron reflectivity measurements simultaneously.

Mikhail Kostylev at the beam line of ANSTO’s Platypus polarised-neutron reflectivity instrument. He is placing a magnetic film into the path of Platypus’s neutron beam.

List of our most important publications within the last 3 years (sorted as latest to oldest)

Maksymov, I.S.; Kostylev, M. Magneto-Electronic Hydrogen Gas Sensors: A Critical Review. Chemosensors 10, 49 (2022). https://doi.org/10.3390/chemosensors10020049
S. Khan a, N.B. Lawler, A. Bake, R. Rahman, D.C. K. Swaminathan Iyer, M. Martyniuk and M. Kostylev, “Iron oxide-Palladium core-shell nanospheres for ferromagnetic resonance-based hydrogen gas sensing”, Inter. J. Hydr. Ener. (2022), https://doi.org/10.1016/j.ijhydene.2021.12.135
A.V. Chumak et al., “Roadmap on Spin-Wave Computing”, arXiv:2111.00365 (2021).
C. Weiss, M. Bailleul, and M. Kostylev, “Excitation and reception of magnetostatic surface spin waves in thin conducting ferromagnetic films by coplanar microwave antennas. Part I: Theory”, arXiv:2111.11106 (2021)
C. Weiss, M. Grassi, Y. Roussigné, A. Stashkevich, T. Schefer, J. Robert, M. Bailleul and M. Kostylev, “Excitation and reception of magnetostatic surface spin waves in thin conducting ferromagnetic films by coplanar microwave antennas. Part II: Experiment”, arXiv:2111.11111 (2021).
S. Watt, M. Kostylev, A.B. Ustinov, and B.A. Kalinikos, Implementing a Magnonic Reservoir Computer Model Based on Time-Delay Multiplexing, Phys. Rev. Appl. 15, 064060 (2021).
C. Weiss, R. Hubner, M. Saunders, A. Semisalova, J. Ehrler, N. Schmidt, J. Seyd, M. Albrecht, S. Anwar, J. Lindner, K. Potzger, and M. Kostylev, Effects of hydrogen absorption on magnetism in Ni80Fe20/Y/Pd trilayers, Phys. Rev. B 104, 094429 (2021).
T.A. Schefer, M. Martyniuk, and M. Kostylev, “Effect of Hydrogen Gas on Ferromagnetic Resonance Properties of Ni-Co-Pd Ternary Alloy Films”, IEEE Trans. Mag. 57, 6100505 (2021).
S. Watt, M. Kostylev, and A.B. Ustinov, “Enhancing computational performance of a spin-wave reservoir computer with input synchronization”, J. Appl. Phys. 129, 044902 (2021).
S. Watt and M. Kostylev, Manipulation of the inverse spin Hall effect in palladium by absorption of hydrogen gas, Phys. Rev. B 101, 174422 (2020).
G.L Causer, M. Kostylev, D.L Cortie, C. Lueng, S.J. Callori, X.L. Wang, XL and F. Klose, In Operando Study of the Hydrogen-Induced Switching of Magnetic Anisotropy at the Co/Pd Interface for Magnetic Hydrogen Gas Sensing, ACS Applied Materials & Interfaces 11, 35420 (2019).
M. Kostylev and A.A. Stashkevich, Proposal for a microwave photon to optical photon converter based on traveling magnons in thin magnetic films, J. Mag. Mag. Mat. 484, 329 (2019).
M. Kostylev, A.B. Ustinov, A.V. Drozdovskii, B.A. Kalinikos and E. Ivanov, Towards experimental observation of parametrically squeezed states of microwave magnons in yttrium iron garnet films, Phys. Rev. B 100, 020401 (2019).

Contact

For new and exciting opportunities you can contact:

mikhail.kostylev@uwa.edu.au

+61 8 6488 2723