Structural first-order transformation in La2/3Ba1/3MnO3: ESR study

We have studied by the electron-spin resonance (ESR) and static magnetic field techniques, the La2/3Ba1/3MnO3 perovskite, which was previously shown to exhibit a martensitic phase transformation in the vicinity of Ts∼200 K [Physical Review B 68, 054109 (2003)], leading to its structural phase-segregated state. Resonant absorptions reveal that in the temperature interval from 100 K to 340 K the compound represents a mixture of two ferromagnetic phases possessing different magnetizations, in varying proportions depending on the temperature, and a small amount of a paramagnetic phase. The results agree well with the previous neutron diffraction study. Applied in the ESR experiments, magnetic fields (2–6 kOe) strongly affect the magnetization curves: even magnetic field as high as 700 Oe modifies the anomaly in the phase transformation region and removes the difference between the zero-field cooled and field-cooled magnetization curves, which implies that the difference in the magnetic susceptibility of the coexisting phases is small and the magnetic domain configuration can be easily changed.

► The electron-spin resonance study of La2/3Ba1/3MnO3 compound has been done.
► Phase segregated state of the compound below the room temperature was revealed.
► The two different FM phases in varying proportions depending on the temperature are coexistent.
► The phase separation originates from the martensitic transformation in 200 K region.
► Magnetic fields up to 6 kOe strongly affects the martensitic phase transformation.