Selected Publications

Towards a standard spin Seebeck measurement

Whilst there have been several reports of the spin Seebeck effect to date, comparison of the absolute voltage(s) measured, in particular for thin films, is limited. In this letter we demonstrate normalisation of the spin Seebeck effect for magnetite:Pt samples deposited on glass with respect to the heat flow, Jq, and temperature difference,  ΔT. We show that the choice of substrate can have a significant impact on the measured spin Seebeck voltage irrespective of the sample quality. Finally, we present a spin Seebeck coefficient for substrate independent characterization of the spin Seebeck effect.

arXiv:1705.02491 [cond-mat.mes-hall]

Demonstration of polycrystalline thin film coatings on glass for spin Seebeck energy harvesting

The spin Seebeck effect in polycrystalline Fe3O4:Pt bilayers deposited onto amorphous glass substrates with a view for economically viable energy harvesting is presented. Crucially, these films exhibit large coercive fields (197 Oe) and retain 75% of saturation magnetisation, in conjunction with energy conversion comparable to epitaxially grown films. This demonstrates the potential of this technology for widespread application in harvesting waste heat for electricity.

Physica Status Solidi: RRL 2016

Overview of the Characteristic Features of the Magnetic Phase Transition with Regards to the Magnetocaloric Effect: the Hidden Relationship Between Hysteresis and Latent Heat

The relation ship between latent heat and its associated hysteresis is reviewed for a series of promising magnetocaloric materials. We show that itinerant magnets appear to consistently show large entropy change accompanied by small hysteresis, compared to local moment systems.

MMTE 2014

Identifying the critical point of the weakly first-order itinerant magnet DyCo2 with complementary magnetization and calorimetric measurements

For itinerant metamagnets, the point at which the phase transition becomes continuous is not always easy to determine. We determine th ecritical point of the weak itinerant magnet DyCo2 using microcalorimetry and magnetometry. The result indicates that the Banerjee criterion is not always applicable.

Phys. Rev B, 2013

Evaluation of the reliability of the measurement of key magnetocaloric properties: A round robin study of La(Fe,Si,Mn)H conducted by the SSEEC consortium of European laboratories

A round robin exercise where the same sample was measured in a consortia of laboratories in order to highlight potential discrepancies between data.

Int. J. Refrig., 2012

Defining the First Order Phase Transition: Hall Probe Imaging

We demonstrate the distinction between the continuous and first order phase transition in a single system with a tri-critical point.

Phys. Rev. B, 2009

Metamagnetism Seeded by Nanostructural Features of Single-Crystalline Gd5Si2Ge2

Using Hall probe imaging we show how the metamagnetic phase transition in Gd5Si2Ge2 is influenced by a secondary paramagnetic phase that nucleate the phase transition on field increase.

Advanced Materials, 2009