Samarium Cobalt Block Magnets at Magnetop Magnetics offer a wide selection of samarium cobalt block magnets, ranging from 10mm to 50mm in length. These samarium cobalt (SmCO) magnetic blocks are made of the alloy of samarium and cobalt. Samarium cobalt magnet has a strength similar to neodymium magnets'. Sometimes a Strong Samarium Cobalt Magnet makes a much better choice than Neodymium as they retain their magnetic strength in much higher or much lower temperature settings. Another characteristic is samarium cobalt magnets fight off corrosion in outdoor or other potentially wet settings much better than neodymium magnets.