Neodymium magnets are very strong in comparison to their mass, but are also mechanically fragile. Like other ferromagnetic materials, neodymium magnets lose their magnetism above a temperature known as the Curie point . But the most powerful grades lose their magnetism at a relatively low temperature: 80 degrees Celsius (176 degrees Fahrenheit ) and above. High-temperature grades will operate at up to 200 and even 230°C but their strength is only marginally greater than that of a samarium-cobalt magnet .