Bipolar Resistive Switching Characteristics of HfO2/TiO2/HfO2 Trilayer-Structure RRAM Devices on Pt and TiN-Coated Substrates Fabricated by Atomic Layer Deposition.

See more Hafnium products. Hafnium (atomic symbol: Hf, atomic number: 72) is a Block D, Group 4, Period 6 element with an atomic weight of 178.49. The number of electrons in each of Hafnium's shells is 2, 8, 18, 32, 10, 2 and its electron configuration is [Xe] 4f¹⁴ 5d² 6s². The hafnium atom has a radius of 159 pm and a Van der Waals radius of 212 pm. Hafnium was predicted by Dmitri Mendeleev in 1869 but it was not until 1922 that it was first isolated Dirk Coster and George de Hevesy. In its elemental form, hafnium has a lustrous silvery-gray appearance. Hafnium does not exist as a free element in nature. It is found in zirconium compounds such as zircon. Hafnium is often a component of superalloys and circuits used in semiconductor device fabrication. Its name is derived from the Latin word Hafnia, meaning Copenhagen, where it was discovered.

See more Titanium products. Titanium (atomic symbol: Ti, atomic number: 22) is a Block D, Group 4, Period 4 element with an atomic weight of 47.867. The number of electrons in each of Titanium's shells is [2, 8, 10, 2] and its electron configuration is [Ar] 3d² 4s². The titanium atom has a radius of 147 pm and a Van der Waals radius of 187 pm. Titanium was discovered by William Gregor in 1791 and first isolated by Jöns Jakob Berzelius in 1825. In its elemental form, titanium has a silvery grey-white metallic appearance. Titanium's properties are chemically and physically similar to zirconium, both of which have the same number of valence electrons and are in the same group in the periodic table. Titanium has five naturally occurring isotopes: ⁴⁶Ti through ⁵⁰Ti, with ⁴⁸Ti being the most abundant (73.8%). Titanium is found in igneous rocks and the sediments derived from them. It is named after the word Titanos, which is Greek for Titans.