On the origin of the giant isotopic effect of hydrogen on the magnetic properties of YFe2A4.2 (A5H, D): A high pressure study

International audienceIn order to identify the origin of the giant isotope effect observed on the magnetic properties of YFe2A4.2 compounds (A¼H, 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 0K, VC¼501.760.3 ˚A3, was demonstrated. This consequently established the crucial role of volume on the huge isotope effect observed on the magnetic properties