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Royal Society University Research Fellow

BSc University of Barcelona
PhD University of Barcelona

Thermal materials

My research focuses on phase transitions in functional materials whose thermal, structural, magnetic and electrical properties display strong coupling. These materials include multiferroics, and offer plenty of scope for interesting science and useful applications.

Caloric effects

Magnetocaloric, electrocaloric and mechanocaloric effects are reversible thermal changes that occur in magnetically, electrically and mechanically responsive materials due to changes in magnetic field, electric field and stress field. These caloric effects are largest near magnetic, ferroelectric and structural phase transitions, and promise new solid-state cooling technologies. I aim to develop new caloric materials systems by exploiting different types of coupling within and between materials.

Magnetoelectric effects

Magnetoelectric coupling permits an electrical polarization to be modified by magnetic field (direct effect), or a magnetization to be modified by electric field (converse effect). I investigate geometry-dependent strain-mediated coupling between ferroelectric materials and ferromagnetic materials near phase transitions. These systems yield large magnetoelectric effects at room temperature, and are interesting for applications in sensors, actuators and data storage.

A. Giant barocaloric effect in in ferrielectric ammonium sulphate [Nature Communications 6, 8801 (2015)]. 

 

B. Giant extrinsic magnetocaloric effect in thin-film La0.7Ca0.3MnO3 on a BaTiO3 substrate [Nature Materials 12, 52 (2013)].

 

C. Giant-strength intrinsic electrocaloric effect in a BaTiO3 single crystal [Advanced Materials 25, 1360 (2013)].

 

  • X. Moya and N. D. Mathur, “Caloric materials for cooling and heating”, Science 370, 797 (2020)
  • 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)
  • A. Aznar, P. Lloveras, J. Kim, E. Stern-Taulats, M. Barrio, J. Ll. Tamarit, C. F. Sánchez-Valdés, J. L. Sánchez Llamazares, N. D. Mathur, and X. Moya, “Giant and reversible inverse barocaloric effects near room temperature in ferromagnetic MnCoGeB0.03”, Advanced Materials 31, 1903577 (2019)
  • P. Lloveras, A. Aznar, M. Barrio, Ph. Negrier, C. Popescu, A. Planes, L. Mañosa, E. Stern Taulats, A. Avramenko, N. D. Mathur, X. Moya, and J.-Ll. Tamarit, “Colossal barocaloric effects near room temperature in plastic crystals of neopentylglycol”, Nature Communications 10, 1083 (2019)
  • X Moya, E Defay, ND Mathur and S Hirose, “Electrocaloric effects in multilayer capacitors for cooling applications”, MRS Bulletin 43, 291 (2018)
  • E Stern-Taulats, T Castán, Ll Mañosa, A Planes, ND Mathur and X Moya, “Multicaloric materials and effects”, MRS Bulletin 43, 295 (2018)