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Royal Society University Research Fellow

BSc University of Barcelona
PhD University of Barcelona

Phase transitions in functional 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, 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).
  • A Aznar, P Lloveras, M Romanini, M Barrio, J-Ll Tamarit, C Cazorla, D Errandonea, ND Mathur, A Planes, X Moya and Ll Mañosa, “Giant barocaloric effects over a wide temperature range in superionic conductor AgI”, Nature Communications 8, 1851 (2017).
  • P Lloveras, E Stern-Taulats, M Barrio, J-Ll Tamarit, . Crossley, W Li, V Pomjakushin, A Planes, Ll Mañosa, ND Mathur and X Moya, “Giant barocaloric effects at low pressure in ferrielectric ammonium sulphate”, Nature Communications 6, 8801 (2015).
  • X Moya, E Defay, V Heine and ND Mathur, “Too cool to work”, Nature Physics 11, 202 (2015).
  • X Moya, S Kar-Narayan and ND Mathur, “Caloric materials near ferroic phase transitions”, Nature Materials 13, 439 (2014).