PRESSURE AND TEMPERATURE DEPENDENCIES OF ELECTRON PARAMAGNETIC RESONANCE Mn^{2 +} UNDER PHASE TRANSITIONS IN Zn(ClO₄)₂ • 6H₂O AND Mg(C1O₄)₂ • 6H₂O

Abstract

EPR spectrum for Mn^{2 +} (3d⁵) ions in crystals Zn(ClO₄)2 • 6H₂0 and Mg(ClO₄)₂ • 6H₂O 6H₂O are studied within a wide range of hydrostatic pressures and temperatures. It is shown that the pressure increase leads to a decrease in the initial splitting for Mn^{2 +} ions in all temperature range. In Zn(ClO₄)2 • 6H₂O (T ₁=71 K, T ₂ =290 K, T ₃ =347 K) and Mg(ClO₄)₂-6H₂O (7"i =108K, r₂=273K, 7/₃-325K) three phase transitions are observed. The hydrostatic pressure increase leads to a linear increase of T ₂ and T₃ and non linear decrease of T ₁ . The low-temperature phase (T ₁<T) disappears under P > 6kbar.

Keywords:

• EPR
• Perchlorate
• High pressure
• 3d ions