Temperature Dependence of Resistivity of Sintered Rare-Earth Permanent-Magnet Materials

• Published in: IEEE transactions on magnetics Vol. 46; no. 1; pp. 15 - 20
• Main Authors: Ruoho, S., Haavisto, M., Takala, E., Santa-Nokki, T., Paju, M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.01.2010; Institute of Electrical and Electronics Engineers
• Subjects: Anisotropic magnetoresistance; Applied sciences; Conductivity; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Iron; Magnetic materials; Magnetic properties; Magnetization; Magnets; Manufacturing; Materials science; Metals. Metallurgy; Other topics in materials science; permanent magnet; Physics; Powder metallurgy. Composite materials; Production techniques; rare-earth; resistivity; Sintered metals and alloys. Pseudo alloys. Cermets; Temperature dependence; Temperature distribution; permanent magnet; Temperature; Electrical conductivity; Electrical properties; Conductivity; Permanent magnets; Sintered alloy; Sintered materials; Powder metallurgy; Temperature effects; Rare earths; Sintering; rare-earth; Magnetic properties; resistivity
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2009.2027815

We studied the resistivity of rare-earth permanent-magnet materials over the temperature range -40°C to +150°C. We investigated three different materials from four manufacturers, including Nd 2 Fe 14 B, SmCo 5 , and Sm 2 Co 17 , and measured their resistivities and temperature coefficients. We found that rare-earth permanent-magnet materials show an anisotropic resistivity behavior. In fact, the resistivity anisotropy causes larger resistivity difference than the temperature variation within the range studied. In many applications, such as permanent-magnet motors, this behavior has to be taken into account in design.