Direct evidence of magnetostructural phase separation in the electron-doped manganiteCa0.8Sm0.16Nd0.04MnO3by means of high magnetic field studies

Abstract

The structural and magnetic properties of ${\text{Ca}}_{0.8}{\text{Sm}}_{0.16}{\text{Nd}}_{0.04}{\text{MnO}}_{3}$ have been investigated by synchrotron x-ray powder diffraction in pulsed magnetic fields in connection with resistivity and magnetization measurements (in static and pulsed magnetic fields). Below 100 K, the spontaneous $(B=0)$ low-temperature phase is found to be structurally and magnetically phase segregated, a major antiferromagnetic monoclinic $P{2}_{1}/m$ phase coexisting with a minor antiferromagnetic orthorhombic Pnma phase containing ferromagnetic clusters. Upon the application of a magnetic field, two magnetic transitions occur: a first transition without structural changes at low field, showing the superparamagnetic like behavior of ferromagnetic domains, followed by a metamagnetic transition. The latter is clearly accompanied by field-induced structural changes, the orthorhombic phase growing at the expense of the monoclinic one.