| Temperature dependence of the gap in the density of states near the Fermi level in a hole doped manganite (2005) | |||||||||
Abstract | |||||||||
| In this paper, we report a model-based quantitative analysis of temperature dependent scanning tunneling spectroscopy (STS) data taken on epitaxial thin films of the hole doped manganite $La_{0.7}Ca_{0.3}MnO_{3}$. The film, grown on lattice matched $NdGaO_{3}$ substrate, has a ferromagnetic transition temperature $T_{c}$ = 268 K. The analysis allows us to evaluate how the tunneling curve evolves across the transition temperature. We find that there is a gap Delta the density of states (DOS), which peaks at T approximate to $T_{c}$. The gap closes in the ferromagnetic state following the evolution of the magnetization. The gap closing is gradual and not sudden at T = $T_{c}$. Above $T_{c}$ the gap reduces from the peak value and reaches a limiting value of approximate to 75 meV for T/$T_{c}$ \geq 1.1 which is close to the value of 60 meV seen from transport experiments. | |||||||||
Publication details | |||||||||
| |||||||||