Structural, magnetic and thermal properties of semiconducting ZnCr ₂Se ₄ - single crystals doped with holmium.

Анотація

Magnetic spinels with general formula AB2X4 (A and B are transition-metal ions, X is a chalcogenide ion), are attractive because of their thermoelectric properties, which have potential application in thermoelectric devices. Moreover, spinels can be applied in chemical industry as catalysts and ceramic carriers catalysts, as well as, in electronics, nuclear energy and many more industries [1]. Therefore, seleno-spinels are promising compounds for this purpose [2] due to rather large cubic unit cell of 10Å, a large ion radius of selenium (1.98Å) and its covalence. ZnCr2Se4 crystallizes in the cubic structure (Fd-3m). Pure ZnCr2Se4, both in mono- and polycrystalline form combines p-type semiconducting conductivity and a helical antiferromagnetic (AFM) order below the Néel temperature TN = 20K with a strong ferromagnetic (FM) component evidenced by a large positive Curie-Weiss temperature () of 115 K.