Infield X-ray diffraction studies of field and temperature driven structural phase transition in Nd0.49Sr0.51MnO3+δ

Abstract

Comprehensive X-ray diffraction (XRD) studies have been performed at different temperature (T) (4.2–300K) and magnetic field (H) (0–8T) to understand the evolution of crystal structure of Nd0.49Sr0.51MnO3+δ (NSMO) under non ambient conditions. The T dependent XRD results show the abrupt change in the lattice parameters without any change in lattice symmetry at ∼200K, which is associated with the first order structural phase transition from ferromagnetic to antiferromagnetic phase. This phase transition is strongly H dependent and shifted to lower temperature (∼150K) on the application of 8T field with phase coexistence (high temperature phase ∼18%), even down to 4.2K. Isothermal XRD results at 150K under different H clearly illustrate the H induced first order structural phase transition. The critical H at which this phase transformation starts is ∼1T, with rapid growth above 4T with hysteretic nature during increasing and decreasing H. These results are supported with the resistivity and magnetoresistance results and affirm the strong spin-lattice coupling in NSMO. Our detail studies reveal the structural correlations to the observed colossal magnetoresistance and magnetocaloric effect in this material.