Temperature and magnetic field induced structural transformation in Si doped CeFe2: in-field x-ray diffraction study

Using x-ray powder diffraction technique at various temperatures and applied magnetic fields, we have studied the magnetostructural properties of Ce(Fe0.95Si0.05)2. The x-ray diffraction data establish quantitative relationships between bulk magnetization and the evolution of structurally distinct phases with magnetic field and temperature, and confirm the distinct features of first order phase transition like supercooling and superheating, metastability, and phase co-existence of different structural polymorphs. We observe the lattice volume mismatch across the structural phase transition, which appears to be the cause for the step behavior of the magnetization isotherms at low temperatures. The present study shows that the lattice distortion has to be treated explicitly, like spin, along with the effects of lattice-spin coupling to account for the magnetization behavior of this system. This structure template can resolve the issue of kinetics in this material as observed in different time scale measurements and with different experimental protocols.

Arabinda Haldar, Niraj K. Singh, Ya. Mudryk, K. G. Suresh, A. K. Nigam, V. K. Pecharsky · 2010