Electronic structure and magnetic properties of the ThxY1−xCo4B solid solution

Detailed theoretical and experimental investigations of the electronic and magnetic properties of the ThxY1−xCo4B compounds have been performed. The neutron powder diffraction shows that by Th for Y substitution, Th atoms occupy preferentially one (1a) of the two Y sites (1a and 1b). The preferential occupation on 1a and 1b crystal sites investigated by theoretical calculations is in good agreement with powder neutron diffraction results. The magnetic properties of the ThxY1−xCo4B compounds are strongly influenced by the Th content x. The Curie temperature of the compound decreases with Th content from 380 K for YCo4B to 303 K for ThCo4B. The Th for Y substitution alter the magnetic coupling of the Co 2c atoms, which have the dominant contribution to the magnetization of the system. The magnetic moments behavior in the ThxY1−xCo4B compounds is also related to the preferential occupation of crystallographic 1a and 1b sites by Th and Y atoms, respectively. The agreement between the calculated magnetic moments and the corresponding experimental results is discussed. All theoretical investigations of the electronic and magnetic properties of the system have been done using the Korringa-Kohn-Rostoker (KKR) band structure method in the ferromagnetic state. The substitutional disorder in the system has been accounted for by means of Coherent Potential Approximation (CPA).