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Professor of Materials Physics
APS Fellow

MA University of Cambridge
PhD University of Cambridge

Thin Films and Devices

My group uses thin films and devices to study the physics of materials that display notable electrical and magnetic properties. Thin films present large areas for interfacing and imaging, and can be used to fabricate devices that address technological challenges.

Electrocaloric materials

Thermal changes that arise in response to changes of voltage are known as electrocaloric effects, and large electrocaloric effects associated with phase transitions in ferroelectric materials could be exploited for solid-state heat pumps. Following our demonstration of large electrocaloric effects in thin films [Science 311 (2006) 1270], the field is young once more, and we are studying a range of electrocaloric materials, devices, and measurement protocols.

Magnetoelectric devices

The magnetization of magnetic materials is traditionally modified using an applied magnetic field, but there is now great interest in using an applied electric field instead (magnetoelectric effects). We have earlier shown that a voltage can drive large magnetic changes in ferromagnetic films via strain from juxtaposed ferroelectric materials [Nature Materials 6 (2007) 348]. The materials may be continuous, or lithographically patterned into smaller elements, ultimately for data storage applications. We are currently focussing on imaging the electrically driven changes in both types of material.


Electrons possess spin as well as charge and can therefore be used to carry magnetic information, giving rise to the field of spin electronics, i.e. spintronics. Having previously demonstrated long-distance spin transport in carbon nanotubes [Nature 445 (2007) 410], we are now investigating long-distance spin transport in graphene. Ultimately one can envisage possible applications for logic and memory.

Size and cost comparison for a one-cent multilayer capacitor that inadvertently functions as a room-temperature magnetic-field sensor that requires no electrical power [A one-cent room-temperature magnetoelectric sensor. C Israel, ND Mathur & JF Scott, Nature Materials 7, 93-94 (2008)].


  • B. Nair, T. Usui, S. Crossley, S. Kurdi, G. G. Guzmán-Verri, X. Moya, S. Hirose and N. D. Mathur, "Large electrocaloric effects in oxide multilayer capacitors over a wide temperature range", Nature 575, 468 (2019)
  • S. Crossley, B. Nair, R. W. Whatmore, X. Moya and N. D. Mathur, "Electrocaloric cooling cycles in lead scandium tantalate with true regeneration via field variation", PRX 9, 041002 (2019) 
  • M. Ghidini, R. Mansell, F. Maccherozzi, X. Moya, L. C. Phillips, W. Yan, D. Pesquera, C. H. W. Barnes, R. P. Cowburn, J.-M. Hu, S. S. Dhesi and N. D. Mathur, "Shear-strain mediated magnetoelectric effects revealed by imaging", Nature Materials 18, 840 (2019)
  • E Defay, G Despesse, R Faye, H Strozyk, D Sette, S Crossley, X Moya and N D Mathur, "Enhanced electrocaloric efficiency via energy recovery", Nature Communications 9, 1827 (2018)