The magnetism and transport properties of heavily doped perovskite ${\mathrm{LaMn}}_{1-x}{\mathrm{Fe}}_x{\mathrm{O}}_3(0.00⩽x⩽0.40)$ were studied. For the doped samples, there is a paramagnetic–ferromagnetic (PM–FM) transition both under zero field cooling and 0.01 Tesla field cooling condition but there is no insulator–metal transition. The curves are fitted well by the thermal activation model. The Mössbauer spectra of heavily doped samples demonstrate that the doped Fe ions are trivalent. In electron spin resonance spectra, many individual ferromagnetic resonance lines occur besides the normal paramagnetic resonance lines at $\mathit{T}>{\mathit{T}}_C$ and then submerge in PM or FM lines at low temperature. We suggest that there is the probability of double exchange interaction between ${\mathrm{Fe}}^{3+}$ ions and ${\mathrm{Mn}}^{3+}$ ions in ${\mathrm{LaMn}}_{1-x}{\mathrm{Fe}}_x{O}_3$.

• Received 28 February 2003

DOI:https://doi.org/10.1103/PhysRevB.70.014422