On the origin of the giant isotopic effect of hydrogen on the magnetic properties of YFe2A4.2 (A = H, D): A high pressure study

Abstract

In order to identify the origin of the giant isotope effect observed on the magnetic properties of YFe2A4.2 compounds (A = H, D) and probe the role of the cell volume difference, we have compared the effect of hydrostatic pressure up to 1.0 GPa on the ferro-antiferromagnetic transition temperatures TF-AF and spontaneous magnetization of YFe2D4.2 and YFe2H4.2. Using compressibility value of 0.013 GPa−1 and the remarkably different negative pressure slopes of TF-AF, the existence of critical volume where the ferromagnetism is suppressed at 0 K, VC = 501.7 ± 0.3 Å´3, was demonstrated. This consequently established the crucial role of volume on the huge isotope effect observed on the magnetic properties.