Pyrochlore magnets of the form $R_2{B}_2{\mathrm{O}}_7$, in which rare-earth ions on the $R$ site form a three-dimensional network of corner-sharing tetrahedra, provide a canonical setting for geometrical frustration. Ho-based pyrochlores host a dipolar spin-ice ground state, characterized by Ising moments constrained by the ice rules and elementary excitations analogous to magnetic monopoles. Here we examine how controlled chemical disorder influences this state by introducing site mixing on the nonmagnetic $B$ site in two compounds. ${\mathrm{Ho}}_2{\mathrm{GaSbO}}_7$ contains only ${\mathrm{Ga}}^{3+}/{\mathrm{Sb}}^{5+}$ charge disorder, whereas ${\mathrm{Ho}}_2{\mathrm{ScSbO}}_7$ exhibits both charge and substantial size disorder arising from the large ionic-radius mismatch between ${\mathrm{Sc}}^{3+}$ and ${\mathrm{Sb}}^{5+}$. Although both materials retain the pyrochlore structure, neutron-scattering measurements reveal a reduced correlation length for the $R/B$-site cation ordering and enhanced local structural distortions in ${\mathrm{Ho}}_2{\mathrm{ScSbO}}_7$. Despite these structural differences, bulk thermodynamic measurements and magnetic diffuse scattering demonstrate that both systems exhibit the defining signatures of a dipolar spin-ice state. Low-energy inelastic neutron spectroscopy further uncovers broad magnetic excitations that develop within the dipolar spin-ice regime, a feature absent in pristine Ho pyrochlores and indicative of disorder-induced splitting of the non-Kramers ground-state doublet. Together, these results show that controlled disorder generates tunable transverse-field-driven quantum fluctuations in Ho-based pyrochlores, although the dipolar spin-ice state is remarkably robust to this disorder.

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• Magnetic anisotropy
• Magnetic interactions
• Magnetic susceptibility
• Magnetism
• Spin dynamics
• Magnetization measurements
• Neutron diffraction
• Neutron pair-distribution function analysis
• Neutron scattering
• Susceptibility measurements
• Time-of-flight neutron spectroscopy