Crystal structure of Zr2Co11 hard magnetic compound

The compound traditionally called Zr2Co11 was studied by X-ray diffraction and electron diffraction in various cast and rapidly solidified ZrCo5.1 specimens including a single crystal. The study reveals two crystal structures. One structure is rhombohedral with arhomb=0.476nm and crhomb=2.42nm. The other structure can be described as orthorhombic with aortho{approximately equal to}arhomb, and cortho=crhomb. It is argued that these two structures correspond to high- and low-temperature Zr2Co11 phases. When cooling the solidified alloy, grains of the low-temperature orthorhombic phase are formed inside grains of the high-temperature rhombohedral phase in accordance with the orientation relations: [001]ortho//[0001]rhomb and . Magnetic measurements indicate that the easy magnetization direction is parallel to [0001]rhomb and [001]ortho. We also observed possible signs of one more, hexagonal, high-temperature Zr2Co11 phase with ahex=arhomb and chex=2crhomb/3.