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Professor of Materials Physics
APS Fellow

MA University of Cambridge
PhD University of Cambridge

Ferroelectric and ferromagnetic materials

We study these materials separately and together using a range of techniques, e.g. producing dense maps of parameter space and vector maps of magnetization. The immediate focus is scientific, the longer-term focus is geared towards applications.

Electrocaloric materials

Electrocaloric effects are highly reversible thermal changes driven by changes of voltage. They are large near ferroelectric phase transitions, and can be used to pump heat. The growing interest that followed our report of large electrocaloric effects in thin films [Science 311 (2006) 1270] has rejuvenated the field, as described in our review article [Nature Materials 13 (2014) 439] that unites electrocaloric materials with magnetocaloric and mechanocaloric materials. We study electrocaloric materials, devices, and measurement protocols.

Magnetoelectric systems

We study magnetoelectric effects in which thin films display magnetic changes due to strain from voltage-controlled ferroelectric substrates, as described in our review article [Nature 442 (2006) 759]. These magnetoelectric effects can be large at planar interfaces [Nature Materials 6 (2007) 348], permitting lithographically patterned elements to be designed for energy efficient data-storage applications. A long-standing collaboration with Diamond Light Source permits ferromagnetic and ferroelectric domains to be imaged using photoemission electron microscopy (PEEM).

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)].
  • D. Pesquera, E. Khestanova, M. Ghidini, S. Zhang, A. P. Rooney, F. Maccherozzi, P. Riego, S. Farokhipoor, J. Kim, X. Moya, M. E. Vickers, N. A. Stelmashenko, S. J. Haigh, S. S. Dhesi and N. D. Mathur, "Large magnetoelectric coupling in multiferroic oxide heterostructures assembled via epitaxial lift off", Nature Communications 11, 3190 (2020) pp 1-8 - DOI: 10.1038/s41467-020-16942-x - See Paper of the Month: "We have lift-off"
  • 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) - DOI: 10.1038/s41586-019-1634-0 - See Paper of the Month: "Survival of the coolest"
  • 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) - DOI: 10.1103/PhysRevX.9.041002 - See Paper of the Month: "Electrocaloric cycles bite back"
  • 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) - DOI: 10.1038/s41563-019-0374-8 - See Paper of the Month: "Shear is the new normal"
  • 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) pp 1-9 - DOI: 10.1038/s41467-018-04027-9 - See Paper of the Month: "Energy recycling"