Revisiting the concept of squareness of engineering magnetic RE-Fe-B materials hysteresis curves

Abstract

The hysteresis loop shape has been a topic of interest within the area of engineering magnetic materials ranging from nano to macro scales. The literature related to its terminology, quantification propositions, significance, and relationships among proposed methods is initially revisited, clarifying potential misconceptions and illustrating its relevance in the hard-magnetic materials area. Next, relationships of the shape of the second quadrant of permanent magnets related to crystallographic alignment, microstructural features/temperature, and chemical composition/processing are discussed focusing on rare-earth-based compounds.