Felicia Gheorghiu (Research Center on Advanced Materials and Technologies, Sciences Department, Alexandru Ioan Cuza University of Iasi), Cristina Ciomaga (Research Department of Physics, Alexandru Ioan Cuza University of Iasi), Mantas Simenas (Lab. of Microwave Spectroscopy, Radio Physics Department, Faculty of Physics, Vilnius University), Mirela Airimioaei (Dielectrics, Ferroelectrics & Multiferroics Group, Department of Physics, Alexandru Ioan Cuza University of Iasi), Juras Banys (Lab. of Microwave Spectroscopy, Radio Physics Department, Faculty of Physics, Vilnius University), Shan Qiao (Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences), Liliana Mitoseriu (Dielectrics, Ferroelectrics & Multiferroics Group, Department of Physics, Alexandru Ioan Cuza University)