Progress has been made in creating artificial pyroelectric materials, usually in the form of a thin film, using gallium nitride (Ga N), caesium nitrate (Cs N O 3), polyvinyl fluorides, derivatives of phenylpyridine, and cobalt phthalocyanine. Lithium tantalate (Li Ta O 3) is a crystal exhibiting both piezoelectric and pyroelectric properties, which has been used to create small-scale nuclear fusion (" pyroelectric fusion "). Recently, pyroelectric and piezoelectric properties have been discovered in doped hafnium oxide (Hf O 2), which is a standard material in CMOS manufacturing.