**Acknowledgements**

We acknowledge the fruitful discussions with Dr. P. Palade. This work was supported by grants of the Romanian Ministry of Research and Innovation, CCCDI – UEFISCDI, project number PN-III-P1-1.2-PCCDI-2017-0062 contract no 58 and project number PN-III-P1-1.2-PCCDI-2017-0871 contract no 47 as well as by the core program at NIMP.

*Magnetic Materials and Magnetic Levitation*
