Giant Electric Field Modulation of Double Exchange Ferromagnetism at Room Temperature in the Perovskite Manganite/Titanate $\mathit{p}-\mathit{n}$ Junction

We report on the electrical modulation of double exchange ferromagnetism at room temperature in hole-doped manganites of a metal oxide $p-n$ junction. In this $\left({\mathrm{La}}_{0.9}{\mathrm{Ba}}_{0.1}\right){\mathrm{MnO}}_3/\mathrm{Nb}$ doped ${\mathrm{SrTiO}}_3$ $p-n$ junction, the temperature dependence of the junction resistance shows a metal-insulator transition whose temperature, corresponding to that of ferromagnetic transition, is hugely modulated from 290 to 340 K by a bias voltage increasing from $+1.0\mathrm{}$ to $+1.8\mathrm{}\mathrm{V}$. The magnetoresistance can also be modulated electrically.