Yttrium, cerium, neodymium, lanthanum as well as trace to minor amounts of other rare earth elements are present in their structure.
en.wikipedia.org The surface of the sodium tantalite crystals is grooved with so called nanosteps that is a result of doping with lanthanum (315 nm range, see nanotechnology).
en.wikipedia.org The oxide is reduced to metal by heating with lanthanum, aluminium, cerium or zirconium in high vacuum.
en.wikipedia.org While these compounds do exist, analogous chemicals that contain lanthanum, praseodymium, gadolinium, holmium, terbium, or ytterbium have not been discovered, as of 2008.
en.wikipedia.org The shorter gap is thanks to a new technique that fabricates epitaxial strontium titanate films with equal concentrations of lanthanum and chromium additives, or dopants.
phys.org