Piezoelectric response in SmFe3 (BO3)4 in a non-piezoactive configuration. Surface piezoelectricity - M. P. Kolodjazhnaja; G. A. Zvjagina; I. A. Gudim; I. V. Bilych; N. G. Burma; K. R. Zhekov; V. D. Fil (Low Temperature Physics, 2017)