Pressure Induced Amorphization of Antiferromagnetic FePO₄ and Fe (OH) ₂

抄録

X-ray diffraction studies were performed in b-FePO₄ and Fe (OH) ₂ In FePO₄, at P=2. 5 (5) GPa, a transformation to a coexisting new crystalline and amorphous phase is observed with about equal abundance. The crystalline phase is identified as VCrO₄-type where Fe^III and P^V ions, are six-fold and four-fold coordinated, respectively. The pressure cycle is hysterectic. The onset of pressure-induced amorphization in Fe (OH) ₂ is at ∼ 1 GPa however is incomplete to the highest pressure (P ∼ 24 GPa). Evidence exists that anisotropic, short-range-order is involved in the amorphization process.