1. Ultrasonic Metrology Department, National Institute of Standards, Giza, Egypt
2. Ferroelectric and Piezoelectric Lab, Physics Department, Faculty of Science, South Valley University, Qena, Egypt
3. Advanced Materials Institute, Central Metallurgical Research and Development Institute, Advanced Materials Institute, Cairo, Egypt
4. Physics Department, Faculty of Science, Menoufia University, Shebin El-Koom, Egypt