China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Is a higher rare earth content always better in neodymium magnets? People often get this wrong when shopping. Although rare earth elements are important, more isn’t necessarily better.
A magnet’s magnetic properties are determined not by quantity, but by phase alignment. Without enough rare earth elements, the magnetism weakens. If there are too many rare earth elements, the crystal arrangement becomes disrupted, affecting performance.
In terms of magnetism, iron is actually stronger than rare earth elements. Once the amount of rare earth elements exceeds the magnetic field’s “sweet spot,” it actually drags down the peak magnetic force. What is the result? The magnetic field becomes weaker and less potent.
Furthermore, the more rare earth elements are mixed in, the harder and more brittle the material typically becomes. This makes it much more difficult to cut, laminate, or move the material.
When temperatures rise, even the highest concentration of neodymium is of no help. What is truly effective? Dysprosium or terbium can perform under thermal stress. Blindly increasing the amount of rare earth elements is completely pointless.
After reading, do you understand? Rare earth content is necessary, but it's not necessarily the higher the better.
You may be wondering;
Main composition and proportion of rare earth neodymium magnets