Element 66 in our International Year of the Periodic Table series is dysprosium. Dysprosium and its compounds are used in some computer hard drives, radiation dosimeters, and motors and generators for electric cars and wind turbines.

Computer hard disk drives contain small amounts of dysprosium compounds in their surface coatings. These dysprosium compounds are highly susceptible to being magnetised and enhance the magnetic properties of hard drives. Data is stored in the hard drive on the basis of this magnetism. Dysprosium isn’t found in newer, solid-state drives, which work on a different basis.

Another magnetic application of dysprosium is in motors and generators. It’s added to neodymium magnets, which can be used in the motors of electric cars and wind turbine generators. This use in electric cars poses a problem as they become more widespread, as the quantity required will exhaust most of the available supply of dysprosium.

Dysprosium can be added to crystals of calcium sulfate or calcium fluoride, which makes them luminescent when exposed to ionising radiation. This is utilised in some radiation dosimeters, which measure this luminescence to determine the levels of radiation to which the dosimeter has been exposed.

Remember, you can keep track of all of the previous entries in this series on the site here, or on the Royal Society of Chemistry’s dedicated page.