The anatase and rutile phases of titanium dioxide (TiO₂) have been widely studied for their photocatalytic and electronic properties, while the brookite phase is rarely explored. The investigations of intrinsic magnetotransport in mixed-phase systems are limited. Magnetic susceptibility and magnetotransport measurements were performed between 2 K and 300 K in magnetic fields up to 12 T. Both samples with different anatase–rutile–brookite ratios exhibit Curie–Weiss susceptibility. Transport measurements reveal an insulating behavior at low temperatures with activation energies 1–20 meV and signatures of variable-range hopping (VRH) conduction. Strong positive magnetoresistance at low temperatures obeys the Efros–Shklovskii VRH model.

Murunskite (K₂FeCu₃S₄) is a layered sulfosalt chalcogenide that occupies a unique position between the cuprate and iron pnictide families: it shares electronic characteristics with the former and adopts the crystal structure of the latter. Despite a completely random distribution of magnetic Fe within a nonmagnetic Cu matrix, murunskite exhibits a well-defined quarter-zone antiferromagnetic transition at 97 K and complete orbital order below 30 K. These findings reveal the unexpected emergence of long-range order in a high-entropy-like environment. This inherent robustness to site disorder in a layered structure makes murunskite a paradigmatic system for further studies. Here, we investigate doping strategies in murunskite to assess how its electronic and magnetic properties can be tuned. Using melt-growth techniques, we achieve substitutions at the magnetic metal site (Fe), spacer cation (K), and sulfur ligand (S), which significantly influence transport and magnetic properties. In addition, we use ionic-liquid gating on the parent compound and observe a gate-dependent suppression of resistivity, confirming the potential for electrostatic control over transport. Our results demonstrate the chemical and electronic plasticity of murunskite, offering a valuable platform for co-engineering disorder, magnetism, and transport, and opening avenues to explore quantum phenomena in correlated and high-entropy materials.