Negative/positive elastocaloric effect associated with vortex domain in the Bi4Ti3O12 ferroelectric nanoparticleB. L. Xu, B. Li, F. Wang, J. B. Wang, X. L. Zhong and W. WangEPL, 115 4 (2016) 47006DOI: https://doi.org/10.1209/0295-5075/115/47006