Crystal-Field Origin of the Giant Magnetocrystalline Anisotropy of PrRu2Si2

R. Michalskia,b, Z. Ropkab and R.J. Radwańskia, b a Institute of Physics, Pedagogical University, Podchorążych 2, 30-084 Kraków, Poland b Center for Solid State Physics, św. Filip 5, 31-150 Kraków, Poland

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PrRu2Si2 shows ferromagnetism below 14 K with the ordered moment of 2.7μB. It exhibits an enormous magnetic anisotropy at 4.2 K with the anisotropy field of about 400 T. We have attrributed the magnetism of PrRu2Si2 to the Pr3+ ions. Thus we performed calculations of the fine electronic structure of the Pr3+ ion in the tetragonal symmetry, relevant to PrRu2Si2, taking into account crystal-field and inter-site exchange interactions. Our calculations reproduce well the zero-temperature moment, the single-crystalline magnetization curves, and giant anisotropy field as 400 T. The magnetocrystalline-anisotropy energy K1 of 59 J/cm3 is the largest known anisotropy - the anisotropy energy of the Nd2Fe14B supermagnet amounts to 12.5 J/cm3 only. Unfortunately, this giant anisotropy is confined to low temperatures only which prohibits its technical applications in the permanent-magnet industry.

DOI: 10.12693/APhysPolA.97.767 PACS numbers: 71.70.-d, 71.20.Eh