Samarium–cobalt 2:17 magnets: Identifying Smn+1Co5n−1 phases stabilized by Zr

The complexities accompanying the interpretation of electron diffraction patterns in the extended Sm–Co alloy system are discussed. The many possibilities of confusing the prominent three phases of the homologous series Smn+1Co5n−1 (n = 2, 3, 4) with each other and with SmCo5 are highlighted, showing the limitations but also the power of this method. The observation of a diffraction pattern that is ostensibly the SmCo5 type does not preclude the possibility that it is actually due to a compound from the series Smn+1Co5n−1.