Magnetic Properties of Neodymium Magnets

Magnetic properties of Neodymium magnets describe their magnetic output, resistance to demagnetization, and the magnetic energy available within a given volume. The most important parameters include remanence Br, coercivity Hcb, intrinsic coercivity Hcj, and maximum energy product (BH)max.

These properties are also the basis of Neodymium magnet grades. Grade designations such as N35, N48, or N52 indicate different energy product levels, while suffixes such as M, H, SH, UH, EH, and AH are associated with higher intrinsic coercivity and temperature capability.

A higher grade number does not automatically mean a better choice for every application. Magnetic output, resistance to demagnetization, operating temperature, magnet geometry, and magnetic circuit conditions should be considered together when comparing Neodymium magnet grades.

The magnetic performance of Neodymium magnets is commonly described by several standard parameters. Understanding these terms makes it easier to read magnet grade specifications and compare different materials.

Neodymium magnet grades are commonly designated by a combination of N + number + optional suffix. The grade designation provides a quick indication of the maximum energy product and intrinsic coercivity of the material, although the complete magnetic property specification should always be checked when selecting a grade.

Suffixes such as M, H, SH, UH, EH, and AH distinguish grades with progressively higher intrinsic coercivity. Typical minimum Hcj levels are approximately:

These grade families are also commonly associated with reference operating-temperature levels of approximately 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, and 220°C, respectively. However, these temperatures should not be treated as fixed material limits. Actual resistance to irreversible demagnetization depends on Hcj, magnet geometry, operating point, temperature, and the surrounding magnetic circuit.

Grades without a suffix, including widely used grades such as N35 and N52, generally belong to the standard coercivity family.

For grain-boundary-diffused Neodymium magnets, some grade systems also use a G prefix to distinguish the manufacturing route from conventional grades.

Neodymium magnet grades should not be compared on a single scale from “lower” to “higher.” The numerical grade primarily reflects the maximum energy product, while suffixes such as H, SH, UH, EH, and AH indicate different intrinsic coercivity levels. Two simple comparisons illustrate the difference.

The following table provides typical magnetic properties for commonly available Neodymium magnet grades, including remanence Br, coercivity Hcb, intrinsic coercivity Hcj, and maximum energy product (BH)max.

Actual specifications may vary between material standards and manufacturers. For critical applications, the required magnetic properties should be confirmed before production.

Selecting a Neodymium magnet grade is not simply a matter of choosing the highest available grade. The appropriate material depends on the required magnetic output, available magnet volume, operating temperature, demagnetizing conditions, and the design of the magnetic circuit.

Required Magnetic Output and Available Space

When magnet dimensions are strongly constrained, grades with higher remanence and maximum energy product can provide more magnetic output from the available volume. This is one of the main reasons for selecting grades such as N48 or N52.

Where sufficient magnet volume is available, however, a lower numerical grade may already satisfy the magnetic requirement. Increasing the grade does not always produce a meaningful improvement in the final magnetic system.

Operating Temperature and Intrinsic Coercivity

Temperature is a major consideration when selecting the coercivity family. As temperature increases, the intrinsic coercivity of Neodymium magnets decreases, increasing the risk of irreversible demagnetization.

Grades with H, SH, UH, EH, or AH suffixes provide progressively higher intrinsic coercivity, but the commonly quoted maximum operating temperatures should be treated as reference values rather than universal limits. The actual requirement depends on both temperature and the operating condition of the magnets.

Magnet Geometry and Magnetic Circuit

The same grade can behave very differently in different magnetic circuits. Thin magnets operating in relatively open magnetic circuits generally experience stronger self-demagnetizing fields than magnets operating with favorable geometry or effective steel return paths.

The permeance coefficient (Pc) is therefore an important consideration when evaluating demagnetization risk. A low operating point may require higher intrinsic coercivity even when the operating temperature itself is not particularly high.

Balance Performance Rather Than Grade Number

The most suitable grade is the one that provides sufficient magnetic output while maintaining an adequate margin against irreversible demagnetization under actual operating conditions. Higher remanence, higher coercivity, temperature capability, material availability, and cost should therefore be balanced rather than optimized independently.

For demanding applications, grade selection should be based on the expected operating point and temperature conditions rather than on a grade designation alone.

Selecting a suitable Neodymium magnet grade requires balancing magnetic output, intrinsic coercivity, operating temperature, magnet geometry, and magnetic circuit conditions.

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