Pyrochlores host a plethora of emergent quantum phenomena such as spin ice, spin liquid, spin glass, topological phases, magnetic monopoles, etc., owing to their unique crystal structure. Here, we investigate the effect of electron doping on the magnetism of a nonmagnetic pyrochlore oxide ${\mathrm{Y}}_2{\mathrm{Ti}}_2{\mathrm{O}}_7$. Preserving the pyrochlore structure, ${\mathrm{Cr}}^{3+}\left(\mathrm{electron}\right)$ is intentionally doped up to $5\%$, which leads to a negligible increase ($<0.02\%$) in the lattice volume. Magnetization measurements reveal a systematic evolution of short-range ferromagnetism below 146 K. A deviation from the anharmonic nature of phonon frequency further validates the presence of such magnetic order. The effect of electron doping is reflected in the reduced band gap as well as enhancement of Pauli susceptibility. To understand the origin of magnetic order, doping-induced mixed valency of Ti and O vacancy is examined through XPS, density functional theory, and electron localization function. Our experimental work, in combination with theoretical analysis, demonstrates an effective way of installing ferromagnetism in nonmagnetic pyrochlores.

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• Noncollinear magnets
• Pyrochlores
• Density functional calculations
• Magnetization measurements
• Raman spectroscopy
• X-ray photoelectron spectroscopy
• X-ray powder diffraction